The boosters on the Victorian Railways X class were actually really successful, and added another 20%ish tractive effort down low. The two that didnt have it fitted were allocated to the flat areas and one of those two even got it retrofitted later, with the other having the idler gear on the bogie from the workshops!
The booster was successful in the US, I guess because the locomotives were larger and had more space under the firebox where the trailing truck sat that it was easier to fit and maintain the boosters. The franklin booster was a sound design with the gear to engage and disengage it, and when done carefully it wouldn't damage those gears. Compare with a unsynchronised gear on a truck. The booster shown with side rods was a kind fitted in place of a tender truck or bogie. But also with the emergence of newer and larger super power in the US the use of boosters got less, having the higher TE available all time was the plus of the new locomotives without boosters.
Mentioned some time back, the Saluda Grade locomotives of the Southern Railway here in the US, were one of the furthest developments of this idea. These locomotives were 2-8-2 locomotives which had driving tenders. Either 2-8-0, or 2-6-0, built from obsolete locomotives. These powered tenders were used to help push, or rarely pull, heavy trains up the steep Saluda grade. Since the locomotives only operated over this one specific section (about 4 miles in length total, up and down the mountain), the Saluda locomotives didn't really experience the loss of traction problems that engines like the Triplex had. So they continued in service until Diesel traction replaced them.
Sounds like the Saluda Grade locomotives were more of a Mallet type locomotive with the engines spread beneath the tenders. Sounds like a great idea. Any idea where I could find a picture of one on line?
A search for "saluda grade powered tender" works for me. Southern Railway Ms-2 - duplex, rather than compound like a Mallet. Probably easier to manage the available adhesion on the tender that way than have to arrange a bypass regulator?
@@cdjhyoung Try searching for "southern railway ms-2". These appear to be simple duplex though, not compound like a Mallet. I suspect the biggest difficulty would have been getting the low-pressure steam pipes from the HP cylinders at the front of the loco, back to the tender. Now if they'd coupled the booster in front, it would have been no use as a tender but at least its weight would have been constant... I think I've just invented the steam loco slug! Apologies if this is a (partial) double post - my original reply disappeared.
@@jonh845 Now that I think about it a bit, having the engine under the tender also introduces the issue of the weight of the tender declining in use and lessening the traction advantage of the engine under the tender.
@@cdjhyoungPretty much, and that was discussed in an older video regarding steam tenders, and also showed a picture of the engine (Or what I believe is one of them) that Original Commenter mentioned of. Though I don’t believe they were as good as they were believed as the ms-2 were converted back to using standard tenders due to lackluster results, and worked until they were phased out in the 1950s, according to the source: “LeMassena, Robert (1979). Articulated Steam Locomotives of North America (1st ed.)” Engines #4535-4539 and #4576, #4561, and engine #5046 were given these steam tenders, but they lost them in 1923, with 5046 losing its steam tender in 1926.
I think that not enough people appreciate the life lessons he puts at the end of every video, I think that they're actually really solid and a great addition to the video. Keep up the great work!
Since I'm too young to do this with alcohol I did it with some apple juice and after that I had so much energy from the sugar I was able to pull the Special Scots express from London to Edinburgh 5 times over with no rest in between at a steady speed of 90 miles an hour I was literally pulling the train, No engine needed
@jamesharding3459 fair... apparently a locomotive refers to the front engine "pulling" the train behind them. And from what I've read, maglevs don't use an engine, but work by propelling every car along the rails, together.
Reminds me of how the Bachmann Emily and Rapido Stirling Single have one more set of powered wheels to increase pulling power. For Bachmann it's the second set of wheels on what would be the front bogie in real life, for Rapido it's the trailing wheels under the cab. Interesting to see how real railways and models can sometimes use the same concepts.
I feel like the boosters were much better in the US than the UK Just look at any of Lima’s superpowered designs. They were the best locomotives at any task they were given. We have so many of their Berkshires around because they were so good.
Honestly not sure any UK application actually needed boosters. The P1 class's intended duty were 100 wagon coal trains, but the loops twixt colliery and London simply weren't long enough to accommodate such long trains, effectively kyboshing the whole proposal before it even got going. Here's a thought ... those coal wagons were all unfitted, making for a pretty hairy operation. Here's another thought ... not even HOW'S protégé Oliver Bulleid employed boosters on any of his designs. If THAT doesn't say something, I dunno what does!!
It's more that the UK loading gauge is comically small for standard gauge, so that didn't help things at all in the UK as far as space for stuff like boosters goes. If you look at roughly contemporary designs from the US and UK with the same wheel arrangement and design specs, the US one is much, much larger - compare for example a PRR K4s to a Gresley A1, the A1 is basically a 2/3 sized K4s.
Lima Locomotive Works used boosters quite often, apparently with great success. It was Lima which pushed the larger firebox and 4-wheel trailing truck, creating their popular 2-8-4.
This was a great watch. I found it pretty hard to find good material on boosters since they're relatively unknown today. Very good of you to also provide the (very impressive) sources.
The Bavarian AA I is an elegant looking experimental engine and I learned something new here. I never knew just how worldwide locomotive boosters were. I'm not surprised to learn that the East Coast US railroads used them but I was surprised to learn how much Gresley experimented with them. I felt that should've been a detail I would've come across in my book about him and his works. Maybe I missed it. Now I have an itch to model locomotive boosters.
South Australian railways 710 & 720 class locomotives had boosters fitted when built, but the 710 class later had theirs removed so they could run on lightly lais track with 60lb rail.
8:20 This appears to be a tender booster, which is a related development. They were usually installed on freight locomotives that didn't have trailing wheels, but could also be added to an existing locomotive more easily than reworking the trailing truck to carry a booster. At the Illinois Railway Museum, we have Lake Superior & Ishpeming #35, a 2-8-0 that was used to haul iron ore in Upper Michigan. The tender booster served it well in that low-speed, high-tonnage service.
I apologize for not getting all the information about the 6-4-2 so here are the details: The steam locomotive of the genus P 3II of the Palatinate Railway was a test locomotive. As with the genre P 3I, it was an Atlantic locomotive (axle sequence 2'B1') with internal cylinders. Unlike the P 3I, however, the P 3II had a composite engine. The most striking feature of the locomotive built by Krauss in 1900 was a starting aid integrated into the front bogie. Between the two axles of the bogie was a third axle, which was driven by a two-cylinder steam engine. This axle was pressed against the rails when starting with the help of a steam cylinder, which increased the friction load from 276.6 kN to 407.1 kN. This construction, which had already been used in a similar form in 1896 at the Bavarian AA I, can be considered a forerunner of the booster. Another special feature of the P 3II were balancing weights attached on both sides of the ash box, which were moved over coupling rods and were intended to compensate for the back and forth masses of the engine. Both innovations did not prove themselves. The auxiliary engine could not be operated reliably, and another problem was the very high axle load of the leading bogie axle when the additional axle was raised, a consequence of the cylinders overhanging forward. The axle was even higher than the driving axles with 145.2 kN. In 1902, the locomotive was rebuilt, whereby both the auxiliary drive and the balancing weights were removed. In addition, the sandbox was moved to the rear, so that both dome axles could now be sanded. The conversion created a still somewhat unusual-looking, but usable locomotive, which was only retired in 1924. In the preliminary redrawing plan of the Deutsche Reichsbahn, the number 14 121 was still provided for them.
Fun fact: the Hudsons actually needed the boosters to start heavier trains - they had less than half their weight on their drivers. The extra wheel on the trailing truck allowed for a larger firebox which made them free steaming and more than capable of pulling heavy trains at speed, but their starting tractive effort was really quite poor because it took more of the weight off the drivers. A J-1a only had about 3800 pounds more tractive effort than a NYC K-5 class Pacific despite 41,000 pounds more weight. That's why they all had boosters, not because it was more economical, but because it was a necessity to make the wheel arrangement more usable.
There were a few reasons why the boosters on the X class were successful. First it had a relatively large boiler. Meaning a good supply of steam. Secondly the engine was on the limits of axle load for general service. Any more tractive effort on the driving wheels would cause them to slip. And any more weight on the driving wheels would be unacceptable. So the booster enabled a "larger" engine without an unacceptable weight gain. At low speeds the booster was running in a far more economical manner than the main drive. Instead of needing a very long cut off with minimal expansion it could run with a better expansion ratio.
Preserved NZR locomotive Kb 968 still got the booster with it while waiting restoration at Mainline Steam in Plimmerton. Perfect to run one from Springfield to Arthur's Pass since these Kb's run just like the 1968 documentary "Kb Country".
Both Canadian Pacific, abd Canadian National had some engines fitted with boosters, primarily for use in Northern Ontario. With Dieselization these engines were bumped down to lighter assignments and the boosters had been removed in the early 1950s. Location under the ash pan diving the second axle of the trailing truck (bogie to you UK people) made them high mainainance items due to acess and fine ash causing wear.
The Canadian Pacific used Boosters on the 2-10-4 T1c Selkirk class engines.... the largest Steam Locomotives in the British Empire. 2 are preserved - 5935 in Montreal, and 5931 in Calgary.
Just had a thought. I've been imagining the concept of steam/electric hybrid locomotives for a while. While the steam cylinders will still be connected to just the main drive wheels, electric motors will be mounted to all wheelsets, including the leading & trailing trucks. This way (at least in theory), locomotives can better utilise their tractive force by powering all wheels to achieve higher acceleration, top speed, & pulling power without using extra steam. Does it sound like a fever dream? Maybe, but that doesn't make it any less interesting to me.
Chesepeak & Ohio made an experimental Locomotive named "JAWN HENERY" which used a steam turbine prime mover to drive a generator supplying electrical power to most, but not all axles. The extra complication of conventional cylender powered drivers was not incorporated. The greater efficency of the diesel prime mover made this a short lived but interesting experiment.
@@jaswmclark Yes, but that's just a series hybrid, where the steam engine can only directly drive the generator before the latter can power the wheels. My concept refers to something like a parallel hybrid, where all wheels can be powered by the steam engine &/or the electric motors at any time. What will really take this concept further in efficiency would be a closed cycle steam system that's compact enough to be installed on a locomotive, drawing electricity from the power grid to eliminate carbon emissions.
Norways biggest locomotives, type 49 Nr. 463, 464, & 465 (Thune/Hamjern 1935) also had boosters, but were nixed on 470, 471(Krupp 1940) & 472, 473(Thune 1941)
Victorian Railways also had one N class 2-8-2 fitted with a booster, this loco hauled circus train most of its life. I once spoke with a fireman who worked this engine and he said the booster made a huge difference compared to a normal N class.
When I was just starting to watch this video, but before getting to the first pictures of booster-equipped locomotives, I was wondering if anybody had tried a booster designed on a lift axle -- and turns out that's exactly what people did in the first few booster designs.
My first car was a 79. 4 speed Corolla. When I'd leave for a trip I'd mount the extra wheels that had the snow tires as they were taller hence more distance covered at a given RPM. Later for burnouts I'd do the opposite with the 70.5 Falcon I had which would snap second gear brake bands on occasion which is part of the automatic transmission. I became very quick in replacing the band on the side of the road with one of the spare two piece bands a transmission shop gave me. Now I use a booster and a five speed for burnouts and overall diameter does not make much difference with all the torque and that transmission thing which steam locomotives didn't have directly but in a way did here. Quick change rear gears for driving the differential is the closest to dual drive wheels on a locomotive which is how I would have tackled their problem.
There booster working in preservation with one of the READING T1s 2100 Locos. She losting during her near scrapping and they recently found one and just finished restoring and putting it back on.
It seems almost tragic that no engineer has thought to combine tradition steam traction good for higher speeds with the high torque of electric motors from stand still. Especially nowadays in preservation with AC/DC regenerative braking. Train of Thought have you not covered the 1930s Dublin Drumm Battery ECUs?
... and steam does high tractive effort from a standstill too (mostly limited by the complexity of driving all the wheels). I'm pretty sure steam with electric has been done - try Douglas Self's Museum of Loco Locos!
Ah. I was confused by the Bavarian bit, since the Bavarian 1400 did also exist as a "booster prototype" of sorts, but looks quite differently. The one showed in the video (and indeed being in Paris in 1900) is not Bavarian, it's, err, whatever the adjective for that is. Palatinian? From the Palatinate, anyway. Completely different, naturally! Apparently this "booster" wasn't reliable and was removed already in 1902, so not much of a service history using it either way (though it continued to be used as a "normal" locomotive until the 20's).
Well, this definitely explains diesel electric train design, and with the current (Edison diesel hybrid type) electrification of trucks we might see things like trailers with powered axles so equipment like logging trucks can get more off-road hill traction by spreading it over even more wheels.
With the understanding that a steam engine can pull a heavy train it can't start, and a diesel can start a heavy train it can't pull. Why not combine the best of both worlds? Take an old diesel electric locomotive and remove everything above the frame. Build a tender body on top but put a diesel generator at the rear. It'll give the steam loco a boost to get started and is a lot less fiddly to operate.
On railroads which had large number of booster equipped steam locomotives, like New York Central, Chesapeake and Ohio, and Southern Pacific, boosters were reasonably successful because most crews were trained to use them, and maintenance shops were properly trained to repair them. On the Pennsylvania, Norfolk and Western, and Santa Fe, boosters were only tried on a few locomotives, and so weren't as highly regarded.
While I'm sure he meant Norfolk and Western, there is a chance he really did mean the old Norfolk Southern Railway en.wikipedia.org/wiki/Norfolk_Southern_Railway_(1942%E2%80%931982)
Sorry ToT, I think you made a mistake at 3:55. When listing the railroads that used boosters on steam locomotives. You said one of them was "...the Norfolk and Southern." The NS didn't exist at the time when steam was the main source of power. Norfolk Southern was formed in 1982. There was a railroad with a similar name: The Norfolk & Western railroad. They tried the boosters when they had steam locomotives. Such as J class #602.
@@lukechristmas3951 I've heard of the Norfolk & Western as well as the Norfolk Southern railways, but I didn't know there was also a Norfolk and Southern Railway too. That just makes the process of explaining railways to non-railfans even more difficult.
some examples of Norwegian NSB type 49 (2-8-4) was also fitted with a booster. and it was unusually enough designed to be used at higher speeds than most other boosters around the world.
I thought the real solution to the need for a booster was when second low pressure cylinders were implemented. When a boost was needed, additional steam could be injected into the exhaust lines from the main cylinders that fed the secondary low pressure cylinders for a boost. The rate of boost could be controlled so it was used efficiently. Am I just dreaming this? I have to have read it somewhere years ago.
It's not the 'internal horsepower' that's limiting it's the tractive effort that can be applied to the rails (drawbar pull in thousands of pounds) before the driven wheel lose traction and slip/spin. The booster truck was used to increase the low speed pull and exploit the ability of the boiler to produce steam by powering more weight carrying wheels. consider 'Shay' pattern logging locomotives for instance, all wheel drive including the tender, slow but very high drawbar pull for the overall weight. there also 'Fairlie', 'Garrett', 'Mallett' and 'Meyer' arrangements which are intended to increase the total amount of weight bearing wheels available for driving and also spread the total weight of the engine across more axles thus reducing the point loading on the track allowing a lighter and cheaper permanent way to be constructed as well as lighter and cheaper civil engineering, think trestle bridges and simple truss and beam bridging etc. 🙂
@@alan-sk7kyAfter thinking about the traction issue, I am wondering if there were examples of the wheels being able to generate more than enough traction to cover certain kinds of slip. I know tow things for certain, locomotives did have the ability to inject high pressure steam into the low pressure cylinder, especially for starting and wheel slip can happen regardless of the power input. I watched a video taken from in the cab of a steam locomotive pulling on level track but it kept spinning out because of wet leaves. It was crazy to see the engineer respond. He had to slam the valve closed then reopen it one or two seconds later. The Shay is the ideal example of your point,. People can walk faster than some Shays.
You fail to mention the booster engines fitted to tender trucks (bogies) in the US. They could be identified by the siderods used to transmit power to a second axle (only one axle was directly powered). Some were applied to the front tender truck, some to the rear truck, and there were examples of 3-axle trucks with the booster engine connecting only two of the axles.
Just add two extra pistons 90° out of phase with the other two pistons. If you use the push pull type it makes any wheel size irrelevant. What's happening is power strokes per surface foot which gives you the torque figure. Increase the power strokes per surface foot and the tractive effort will increase. Power can be controlled via the steam, and all pistons will be power synchronised using link bars on the wheels. This is because you would have to add the 90° out phase pistons on the other wheels due to piston location, or maybe stack them underneath the other pistons? Either way as long as all pistons are hard linked together.
I never understood that why no steam locomotives were made with changeable gearing system. The Shays had steam motors insteed of direkt steam piston drive, yet even those were not fitted with variable gearboxes.
I think the answer is that by varying the cut-off, a correctly sized steam engine can cover the working range well enough without all the complexity of a multi-speed geared transmission. Plus working at low speed / high torque it would be huge!
3:58 I would like to make a point about the norfolk southern railway. It is a class one railway in the us and its fleet is composed of diesel locomotives. The southern and conrail merged to create norfolk southern well after the steam era. Most likely the southern railway with their ps-4 type locomotices
Didn't a "simpling valve" kinda do the same thing, especially starting a train? I know it required both HP and LP cylinders, and "simpling" would route high pressure steam into the low pressure cylinders, boosting power but also using up much more steam.
While true, the simpling valve didn't help with adhesion issues. It gave more raw power from the main cylinders, but if you have a locomotive that's constantly slipping it's wheels with a heavy train (either at startup or slogging it up a grade), adding more power in the cranks driving those same wheels isn't going to do much. The booster applied power to a separate axle, which gave the locomotive more effective traction thanks to the weight resting on that otherwise deadweight axle now being used to apply additional power to the tracks.
@@andrewlucia865 So true-I didn't think about adhesion, merely tractive effort. I guess that's also why they tried powered tenders. More power, AND more traction (with a full tender). But the same drawbacks as these boosters.
So one thing you got wrong. No such thing as Norfolk and Southern. It's actually Norfolk Southern and was a merger between Southern Railway and Norfolk and Western. Which is what I think you meant. That merger happened long after the steam era ended.
There is one way extra traction can be obtained without the complexity of a small donkey engine, you take drive off an engine,s rearmost coupled axle via an upside down top loader spiral bevel spur gearbox on said axle. A prop shaft runs in a heat shield under the firebox to a second bevel gearbox on the trailing truck axle. With steam shut off, via lever in the cab, driver engages a dog or multi disc Heleshaw clutch on the trailing truck axle gearbox, like an old Willy,s Jeep. Once the train reaches 25 mph the booster clutch is disengaged, a lot simpler and lighter.
At that point there seems little reason to disengage it tbh - why not just keep the additional drive all the time? You'd need to size up the cylinders to provide the extra tractive effort, but you'd end up with a loco with more driven axles that can still go round corners, and arguably no heavier or more complex than providing a separate booster. The slightly bigger and heavier motion might be a small drawback at higher speeds, but big and fast locos were built successfully. I like it. Maybe clearance under the firebox would be a limitation... although perhaps you could have a split ashpan with a transmission tunnel through the middle?
@@jonh845 You mean permanent drive to the trailing truck axle ,like a Range Rover or Audi Quattro?, that would help when climbing steep grades with a twelve or thirteen bogie coach train behind the tender. Oliver Bullieds 'Spam Cans' were notorious for slipping, so a permanently driven trailing truck axle is a no brainer.
@@basiltaylor8910 Arguably more like a 4Motion Golf ;-) Would require careful matching of gear ratio and wheel diameter though - tricky as the tyres wear particularly with different nominal sizes. Or you have to use something like a viscous coupling, which feels out of reach of early 1900s technology. Can't use a differential without basically moving to a complete geared drive like a Shay or Heisler.
@@jonh845 Er no , am talking the 1930,s when Dr Henri Foettinger pioneered a compact fluid coupling for Mercedes Daimler Benz, this coupling compensates for wear in tyres of different diameters by slipping just enough and not heat up the oil.
At that time, the norfolk and WESTERN hadnt merged with the SOUTHERN railroad. That wouldnt happen until the late 80s to early 90s, making the norfolk southern.
Fun fact! There is a steam locomotive in the United States that is being restored to operation that has a booster. Boston and Maine railroad No. 3713 "The constitution" is being restored at Steam Town in scranton pennsylvania. Once restored, the locomotive will pull trains for the museum, and according to photos and articles I've seen and read, the booster on the locomotive has been restored and will be put on the locomotive for use. However, this booster is located on the tender, not the locomotive itself. Here is a link to a video on the booster. ua-cam.com/video/4Szhi0BV6N4/v-deo.htmlsi=lOQ0VjyVw0viPuHI
so how is it that the Americans had a good run with boosters, case in point the Lima GS series of locomotive the Southern Pacific ran like the GS 4's one of which is still running all over the US as a tour locomotive. It has a rear truck booster system, and like other models of locomotives purportedly worked very well.
0:50 Correction: Wheels do not do anything to the tractive effort of a locomotive, they change the adhesion. And it's not exclusively the wheels either, it's how far the connecting rods are from the center of the wheel. If they are more than halfway, the engine will have more power at the cost of speed, and vice versa. What primarily changes the tractive effort is the cylinders and the boiler pressure. Faster locomotives have larger wheels so the cylinders don't have to work as hard at higher speeds. Get your facts straight man, 'cause despite what you say, people will take your word as gospel.
Wheel diameter does have an effect on tractive effort. The basic formula for tractive effort is: TE = (d * d * S * P)/D, where d is the diameter of the cylinders, S is the length of the stroke of the cylinder, P is the steam pressure in the cylinder, and D is the diameter of the driving wheels. So increasing the diameter of the driving wheels will have the result of reducing the tractive effort of the locomotive.
I realize I phrased this incorrectly. As you said, they do affect tractive effort. I more so meant to say that they are not the sole factor in tractive effort, but re-reading it I did say that they do nothing. Thank you correcting me!
It's all about where the reverser is, if the reverser is all the way foward you are getting the most power, the closer you bring it to center the faster you go.
The boosters on the Victorian Railways X class were actually really successful, and added another 20%ish tractive effort down low. The two that didnt have it fitted were allocated to the flat areas and one of those two even got it retrofitted later, with the other having the idler gear on the bogie from the workshops!
I wish somebody preserved one of those boosters so we can see the complexity of the mechanics behind it
A Kb class loco still exists and is fitted with a booster. Operational however the loco is not
In the US, the locomotive 2102 still runs with an operational Franklin booster.
The Southern Pacific 4449 has a Booster Engine too
Who knows maybe someone will make a replica of one
@@jeffreymonroe4776they are still around.
The booster was successful in the US, I guess because the locomotives were larger and had more space under the firebox where the trailing truck sat that it was easier to fit and maintain the boosters.
The franklin booster was a sound design with the gear to engage and disengage it, and when done carefully it wouldn't damage those gears. Compare with a unsynchronised gear on a truck.
The booster shown with side rods was a kind fitted in place of a tender truck or bogie.
But also with the emergence of newer and larger super power in the US the use of boosters got less, having the higher TE available all time was the plus of the new locomotives without boosters.
Mentioned some time back, the Saluda Grade locomotives of the Southern Railway here in the US, were one of the furthest developments of this idea. These locomotives were 2-8-2 locomotives which had driving tenders. Either 2-8-0, or 2-6-0, built from obsolete locomotives. These powered tenders were used to help push, or rarely pull, heavy trains up the steep Saluda grade. Since the locomotives only operated over this one specific section (about 4 miles in length total, up and down the mountain), the Saluda locomotives didn't really experience the loss of traction problems that engines like the Triplex had. So they continued in service until Diesel traction replaced them.
Sounds like the Saluda Grade locomotives were more of a Mallet type locomotive with the engines spread beneath the tenders. Sounds like a great idea. Any idea where I could find a picture of one on line?
A search for "saluda grade powered tender" works for me. Southern Railway Ms-2 - duplex, rather than compound like a Mallet. Probably easier to manage the available adhesion on the tender that way than have to arrange a bypass regulator?
@@cdjhyoung Try searching for "southern railway ms-2".
These appear to be simple duplex though, not compound like a Mallet. I suspect the biggest difficulty would have been getting the low-pressure steam pipes from the HP cylinders at the front of the loco, back to the tender. Now if they'd coupled the booster in front, it would have been no use as a tender but at least its weight would have been constant... I think I've just invented the steam loco slug!
Apologies if this is a (partial) double post - my original reply disappeared.
@@jonh845 Now that I think about it a bit, having the engine under the tender also introduces the issue of the weight of the tender declining in use and lessening the traction advantage of the engine under the tender.
@@cdjhyoungPretty much, and that was discussed in an older video regarding steam tenders, and also showed a picture of the engine (Or what I believe is one of them) that Original Commenter mentioned of.
Though I don’t believe they were as good as they were believed as the ms-2 were converted back to using standard tenders due to lackluster results, and worked until they were phased out in the 1950s, according to the source: “LeMassena, Robert (1979). Articulated Steam Locomotives of North America (1st ed.)” Engines #4535-4539 and #4576, #4561, and engine #5046 were given these steam tenders, but they lost them in 1923, with 5046 losing its steam tender in 1926.
I think that not enough people appreciate the life lessons he puts at the end of every video, I think that they're actually really solid and a great addition to the video.
Keep up the great work!
So THAT'S why the New York Central Hudsons had one pair of trailing wheels bigger than the other!
Same with the Southern Pacific’s GS2-GS6 class 4-8-4’s if my memory is correct.
6:45 such a cool looking design
the more you go deeper into railway history, the more uncanningly cohesive cartoonish/fantasiastic locomotive designs feel
Drinking game: take a shot every time he says "booster"
is it counting the title and description
Challenge accepted. Il let you know I survive tomorrow lol
@@KenwayJoelfly high bro🕊🕊🕊
Since I'm too young to do this with alcohol I did it with some apple juice and after that I had so much energy from the sugar I was able to pull the Special Scots express from London to Edinburgh 5 times over with no rest in between at a steady speed of 90 miles an hour I was literally pulling the train,
No engine needed
@@LBSC70 Oh man I've got some boot to fill now. Way to set the bar high pal lol
You can’t be a locomotive without your wheels. Those are always the most important part of a vehicle.
Tell that to a maglev.
@@KelniusTV Unless I’m mistaken, those trains do not involve a locomotive.
@jamesharding3459 fair... apparently a locomotive refers to the front engine "pulling" the train behind them. And from what I've read, maglevs don't use an engine, but work by propelling every car along the rails, together.
@@KelniusTVat least some maglev trains do have wheels for low-speed movement.
Reminds me of how the Bachmann Emily and Rapido Stirling Single have one more set of powered wheels to increase pulling power. For Bachmann it's the second set of wheels on what would be the front bogie in real life, for Rapido it's the trailing wheels under the cab. Interesting to see how real railways and models can sometimes use the same concepts.
I knew I wasn't the only one thinking of that
I feel like the boosters were much better in the US than the UK
Just look at any of Lima’s superpowered designs. They were the best locomotives at any task they were given. We have so many of their Berkshires around because they were so good.
Honestly not sure any UK application actually needed boosters. The P1 class's intended duty were 100 wagon coal trains, but the loops twixt colliery and London simply weren't long enough to accommodate such long trains, effectively kyboshing the whole proposal before it even got going.
Here's a thought ... those coal wagons were all unfitted, making for a pretty hairy operation.
Here's another thought ... not even HOW'S protégé Oliver Bulleid employed boosters on any of his designs. If THAT doesn't say something, I dunno what does!!
It's more that the UK loading gauge is comically small for standard gauge, so that didn't help things at all in the UK as far as space for stuff like boosters goes.
If you look at roughly contemporary designs from the US and UK with the same wheel arrangement and design specs, the US one is much, much larger - compare for example a PRR K4s to a Gresley A1, the A1 is basically a 2/3 sized K4s.
Lima Locomotive Works used boosters quite often, apparently with great success. It was Lima which pushed the larger firebox and 4-wheel trailing truck, creating their popular 2-8-4.
Fun fact: the 4449 (and other gs-4s) have/had a booster on their trailing truck!
This was a great watch. I found it pretty hard to find good material on boosters since they're relatively unknown today. Very good of you to also provide the (very impressive) sources.
The Bavarian AA I is an elegant looking experimental engine and I learned something new here. I never knew just how worldwide locomotive boosters were. I'm not surprised to learn that the East Coast US railroads used them but I was surprised to learn how much Gresley experimented with them. I felt that should've been a detail I would've come across in my book about him and his works. Maybe I missed it. Now I have an itch to model locomotive boosters.
This is something i should invest in when making live models
South Australian railways 710 & 720 class locomotives had boosters fitted when built, but the 710 class later had theirs removed so they could run on lightly lais track with 60lb rail.
8:20 This appears to be a tender booster, which is a related development. They were usually installed on freight locomotives that didn't have trailing wheels, but could also be added to an existing locomotive more easily than reworking the trailing truck to carry a booster. At the Illinois Railway Museum, we have Lake Superior & Ishpeming #35, a 2-8-0 that was used to haul iron ore in Upper Michigan. The tender booster served it well in that low-speed, high-tonnage service.
I love the NER C10s. 4-4-4-4 is so unusual, and I love NER designs in general.
I apologize for not getting all the information about the 6-4-2 so here are the details: The steam locomotive of the genus P 3II of the Palatinate Railway was a test locomotive. As with the genre P 3I, it was an Atlantic locomotive (axle sequence 2'B1') with internal cylinders. Unlike the P 3I, however, the P 3II had a composite engine. The most striking feature of the locomotive built by Krauss in 1900 was a starting aid integrated into the front bogie. Between the two axles of the bogie was a third axle, which was driven by a two-cylinder steam engine. This axle was pressed against the rails when starting with the help of a steam cylinder, which increased the friction load from 276.6 kN to 407.1 kN. This construction, which had already been used in a similar form in 1896 at the Bavarian AA I, can be considered a forerunner of the booster. Another special feature of the P 3II were balancing weights attached on both sides of the ash box, which were moved over coupling rods and were intended to compensate for the back and forth masses of the engine. Both innovations did not prove themselves. The auxiliary engine could not be operated reliably, and another problem was the very high axle load of the leading bogie axle when the additional axle was raised, a consequence of the cylinders overhanging forward. The axle was even higher than the driving axles with 145.2 kN. In 1902, the locomotive was rebuilt, whereby both the auxiliary drive and the balancing weights were removed. In addition, the sandbox was moved to the rear, so that both dome axles could now be sanded. The conversion created a still somewhat unusual-looking, but usable locomotive, which was only retired in 1924. In the preliminary redrawing plan of the Deutsche Reichsbahn, the number 14 121 was still provided for them.
Hope this helps
Fun fact: the Hudsons actually needed the boosters to start heavier trains - they had less than half their weight on their drivers. The extra wheel on the trailing truck allowed for a larger firebox which made them free steaming and more than capable of pulling heavy trains at speed, but their starting tractive effort was really quite poor because it took more of the weight off the drivers. A J-1a only had about 3800 pounds more tractive effort than a NYC K-5 class Pacific despite 41,000 pounds more weight. That's why they all had boosters, not because it was more economical, but because it was a necessity to make the wheel arrangement more usable.
So many innovations in steam engine design didn't succeed because drivers were stuck in their own ways
I love how he incorporates a little motivational quote at the end of all of his videos
There were a few reasons why the boosters on the X class were successful. First it had a relatively large boiler. Meaning a good supply of steam. Secondly the engine was on the limits of axle load for general service. Any more tractive effort on the driving wheels would cause them to slip. And any more weight on the driving wheels would be unacceptable. So the booster enabled a "larger" engine without an unacceptable weight gain. At low speeds the booster was running in a far more economical manner than the main drive. Instead of needing a very long cut off with minimal expansion it could run with a better expansion ratio.
Quick note on the X class: the ONLY class member that survived was X36, which was the only X not fitted with a booster!
Preserved NZR locomotive Kb 968 still got the booster with it while waiting restoration at Mainline Steam in Plimmerton. Perfect to run one from Springfield to Arthur's Pass since these Kb's run just like the 1968 documentary "Kb Country".
Southern Pacific in the US also used them on their GS-4 series locomotives, but phased most out in the 1950s when diesels started replacing them
Thank you for anticipating my comment from the other video 🙂
Both Canadian Pacific, abd Canadian National had some engines fitted with boosters, primarily for use in Northern Ontario. With Dieselization these engines were bumped down to lighter assignments and the boosters had been removed in the early 1950s. Location under the ash pan diving the second axle of the trailing truck (bogie to you UK people) made them high mainainance items due to acess and fine ash causing wear.
The Canadian Pacific used Boosters on the 2-10-4 T1c Selkirk class engines.... the largest Steam Locomotives in the British Empire. 2 are preserved - 5935 in Montreal, and 5931 in Calgary.
The 4449, which originally didn't have one, had one added in in the 1970s restoration of the locomotive
Just had a thought.
I've been imagining the concept of steam/electric hybrid locomotives for a while. While the steam cylinders will still be connected to just the main drive wheels, electric motors will be mounted to all wheelsets, including the leading & trailing trucks.
This way (at least in theory), locomotives can better utilise their tractive force by powering all wheels to achieve higher acceleration, top speed, & pulling power without using extra steam.
Does it sound like a fever dream? Maybe, but that doesn't make it any less interesting to me.
Chesepeak & Ohio made an experimental Locomotive named "JAWN HENERY" which used a steam turbine prime mover to drive a generator supplying electrical power to most, but not all axles. The extra complication of conventional cylender powered drivers was not incorporated. The greater efficency of the diesel prime mover made this a short lived but interesting experiment.
@@jaswmclark Yes, but that's just a series hybrid, where the steam engine can only directly drive the generator before the latter can power the wheels. My concept refers to something like a parallel hybrid, where all wheels can be powered by the steam engine &/or the electric motors at any time.
What will really take this concept further in efficiency would be a closed cycle steam system that's compact enough to be installed on a locomotive, drawing electricity from the power grid to eliminate carbon emissions.
This was very insightful!
Norways biggest locomotives, type 49 Nr. 463, 464, & 465 (Thune/Hamjern 1935) also had boosters, but were nixed on 470, 471(Krupp 1940) & 472, 473(Thune 1941)
Victorian Railways also had one N class 2-8-2 fitted with a booster, this loco hauled circus train most of its life. I once spoke with a fireman who worked this engine and he said the booster made a huge difference compared to a normal N class.
When I was just starting to watch this video, but before getting to the first pictures of booster-equipped locomotives, I was wondering if anybody had tried a booster designed on a lift axle -- and turns out that's exactly what people did in the first few booster designs.
My first car was a 79. 4 speed Corolla. When I'd leave for a trip I'd mount the extra wheels that had the snow tires as they were taller hence more distance covered at a given RPM. Later for burnouts I'd do the opposite with the 70.5 Falcon I had which would snap second gear brake bands on occasion which is part of the automatic transmission. I became very quick in replacing the band on the side of the road with one of the spare two piece bands a transmission shop gave me. Now I use a booster and a five speed for burnouts and overall diameter does not make much difference with all the torque and that transmission thing which steam locomotives didn't have directly but in a way did here. Quick change rear gears for driving the differential is the closest to dual drive wheels on a locomotive which is how I would have tackled their problem.
There booster working in preservation with one of the READING T1s 2100 Locos. She losting during her near scrapping and they recently found one and just finished restoring and putting it back on.
I didn't realize how common boosters were on UK locomotives. SP 4449 still has her booster and has apparently used it on occasion
It seems almost tragic that no engineer has thought to combine tradition steam traction good for higher speeds with the high torque of electric motors from stand still. Especially nowadays in preservation with AC/DC regenerative braking.
Train of Thought have you not covered the 1930s Dublin Drumm Battery ECUs?
Electric motors do high speeds too, so why bother
... and steam does high tractive effort from a standstill too (mostly limited by the complexity of driving all the wheels).
I'm pretty sure steam with electric has been done - try Douglas Self's Museum of Loco Locos!
Ah. I was confused by the Bavarian bit, since the Bavarian 1400 did also exist as a "booster prototype" of sorts, but looks quite differently. The one showed in the video (and indeed being in Paris in 1900) is not Bavarian, it's, err, whatever the adjective for that is. Palatinian? From the Palatinate, anyway. Completely different, naturally!
Apparently this "booster" wasn't reliable and was removed already in 1902, so not much of a service history using it either way (though it continued to be used as a "normal" locomotive until the 20's).
2:30 "this was was 6-4-2 engine"
Whyte notation: are you sure about that
Well, this definitely explains diesel electric train design, and with the current (Edison diesel hybrid type) electrification of trucks we might see things like trailers with powered axles so equipment like logging trucks can get more off-road hill traction by spreading it over even more wheels.
With the understanding that a steam engine can pull a heavy train it can't start, and a diesel can start a heavy train it can't pull. Why not combine the best of both worlds? Take an old diesel electric locomotive and remove everything above the frame. Build a tender body on top but put a diesel generator at the rear. It'll give the steam loco a boost to get started and is a lot less fiddly to operate.
Under what circumstances would a diesel engine be able to start a train, but be unable to pull that same train.
Are you referring to speed?
If I’m not mistaken the Reading & Northerns T-1 class 4-8-4 which were rebuilt from 2-8-0 Consolidations had boosters fitted
On railroads which had large number of booster equipped steam locomotives, like New York Central, Chesapeake and Ohio, and Southern Pacific, boosters were reasonably successful because most crews were trained to use them, and maintenance shops were properly trained to repair them. On the Pennsylvania, Norfolk and Western, and Santa Fe, boosters were only tried on a few locomotives, and so weren't as highly regarded.
2:21 bro looks ai generated
It looks like a unnamed thomas and friends character that you usually see in the background of the set
You called the Norfolk and Western, Norfolk Southern when talking about 1920/30s railroads lol 😂
Well, N&W and Southern did merge to form Norfolk Southern, so it makes sense.
@@AnimalsVehiclesAndMoreStill, NS didn’t exist at that time. So in this case, it is N&W.
While I'm sure he meant Norfolk and Western, there is a chance he really did mean the old Norfolk Southern Railway
en.wikipedia.org/wiki/Norfolk_Southern_Railway_(1942%E2%80%931982)
en.m.wikipedia.org/wiki/Norfolk_Southern_Railway_(1942%E2%80%931982)
Wonderful. Thank you. 🚝🇦🇺
One way boosters were used that I noticed you didn't mention was Tender boosters
Can you please make a video on the history of the Boulder valley railroad in Colorado?
Sorry ToT, I think you made a mistake at 3:55.
When listing the railroads that used boosters on steam locomotives. You said one of them was "...the Norfolk and Southern."
The NS didn't exist at the time when steam was the main source of power. Norfolk Southern was formed in 1982.
There was a railroad with a similar name: The Norfolk & Western railroad. They tried the boosters when they had steam locomotives. Such as J class #602.
Probably just simply said southern instead of western... It isnt that deep. I make the same mistake all the time.
@@M4A2-76_Sherman Maybe, but there is this
en.wikipedia.org/wiki/Norfolk_Southern_Railway_(1942%E2%80%931982)
@@lukechristmas3951 I've heard of the Norfolk & Western as well as the Norfolk Southern railways, but I didn't know there was also a Norfolk and Southern Railway too. That just makes the process of explaining railways to non-railfans even more difficult.
Will you do a Union Pacific 7002 steam engine, please?
I was totally not prepared to see NZR Ja 1271 at 0:09. She is a locomotive I have seen in person, and she is beautiful.
some examples of Norwegian NSB type 49 (2-8-4) was also fitted with a booster. and it was unusually enough designed to be used at higher speeds than most other boosters around the world.
I thought the real solution to the need for a booster was when second low pressure cylinders were implemented. When a boost was needed, additional steam could be injected into the exhaust lines from the main cylinders that fed the secondary low pressure cylinders for a boost. The rate of boost could be controlled so it was used efficiently. Am I just dreaming this? I have to have read it somewhere years ago.
It's not the 'internal horsepower' that's limiting it's the tractive effort that can be applied to the rails (drawbar pull in thousands of pounds) before the driven wheel lose traction and slip/spin. The booster truck was used to increase the low speed pull and exploit the ability of the boiler to produce steam by powering more weight carrying wheels. consider 'Shay' pattern logging locomotives for instance, all wheel drive including the tender, slow but very high drawbar pull for the overall weight. there also 'Fairlie', 'Garrett', 'Mallett' and 'Meyer' arrangements which are intended to increase the total amount of weight bearing wheels available for driving and also spread the total weight of the engine across more axles thus reducing the point loading on the track allowing a lighter and cheaper permanent way to be constructed as well as lighter and cheaper civil engineering, think trestle bridges and simple truss and beam bridging etc. 🙂
@@alan-sk7kyAfter thinking about the traction issue, I am wondering if there were examples of the wheels being able to generate more than enough traction to cover certain kinds of slip. I know tow things for certain, locomotives did have the ability to inject high pressure steam into the low pressure cylinder, especially for starting and wheel slip can happen regardless of the power input. I watched a video taken from in the cab of a steam locomotive pulling on level track but it kept spinning out because of wet leaves. It was crazy to see the engineer respond. He had to slam the valve closed then reopen it one or two seconds later. The Shay is the ideal example of your point,. People can walk faster than some Shays.
Great Video. I’m sure I’ve seen tender fitted boosters somewhere too. Ring any bells for you?
You fail to mention the booster engines fitted to tender trucks (bogies) in the US. They could be identified by the siderods used to transmit power to a second axle (only one axle was directly powered). Some were applied to the front tender truck, some to the rear truck, and there were examples of 3-axle trucks with the booster engine connecting only two of the axles.
That 6-4-2 was a very attractive locomotive actually. Kinda compact yet butch.
The Steam Engine Looks Good I Like It
ToT, Norfolk and Western RR didn't merge with Southern RR until the early 1980's, long after steam locomotives were not in regular use.
Nicely done 0:03
Need this in RRO for trying to pull 15 log cars up a 3.5% with a betsy
3:58 ToT said Norfolk and Southern instead of Norfolk and Western
Some of these things look like Dr. Suess machines
Just add two extra pistons 90° out of phase with the other two pistons.
If you use the push pull type it makes any wheel size irrelevant.
What's happening is power strokes per surface foot which gives you the torque figure.
Increase the power strokes per surface foot and the tractive effort will increase.
Power can be controlled via the steam, and all pistons will be power synchronised using link bars on the wheels.
This is because you would have to add the 90° out phase pistons on the other wheels due to piston location, or maybe stack them underneath the other pistons?
Either way as long as all pistons are hard linked together.
I never understood that why no steam locomotives were made with changeable gearing system. The Shays had steam motors insteed of direkt steam piston drive, yet even those were not fitted with variable gearboxes.
I think the answer is that by varying the cut-off, a correctly sized steam engine can cover the working range well enough without all the complexity of a multi-speed geared transmission. Plus working at low speed / high torque it would be huge!
I think what could have been done was the inclusion of turbines to spin the wheels much like a traction motor in diesel-electric/electric trains.
oh wow, that ludmilla at the beginning got me off guard
3:58 I would like to make a point about the norfolk southern railway. It is a class one railway in the us and its fleet is composed of diesel locomotives. The southern and conrail merged to create norfolk southern well after the steam era. Most likely the southern railway with their ps-4 type locomotices
Didn't a "simpling valve" kinda do the same thing, especially starting a train? I know it required both HP and LP cylinders, and "simpling" would route high pressure steam into the low pressure cylinders, boosting power but also using up much more steam.
While true, the simpling valve didn't help with adhesion issues. It gave more raw power from the main cylinders, but if you have a locomotive that's constantly slipping it's wheels with a heavy train (either at startup or slogging it up a grade), adding more power in the cranks driving those same wheels isn't going to do much. The booster applied power to a separate axle, which gave the locomotive more effective traction thanks to the weight resting on that otherwise deadweight axle now being used to apply additional power to the tracks.
@@andrewlucia865 So true-I didn't think about adhesion, merely tractive effort. I guess that's also why they tried powered tenders. More power, AND more traction (with a full tender). But the same drawbacks as these boosters.
The only Boosters I see on diesels are turbochargers.
NOS eh?
Thomas the Chav engine anyone?
Did you say 'Norfolk and Southern' ?
So one thing you got wrong. No such thing as Norfolk and Southern. It's actually Norfolk Southern and was a merger between Southern Railway and Norfolk and Western. Which is what I think you meant. That merger happened long after the steam era ended.
seems to be the locomotive equivalent of selecting low range in a 4x4...
maybe Gresley secretly wanted to go off-roading?!
Anyone else start seeing Thomas the tank engine and friends, after LNER showed up?
That is called Booster Engine 🚂
They should Have built a Mega Giant Mountain Type 4-12-4 and Hyper Niagara 4-18-4.
1271 is a NZ JA 4-8-2 it is restored and as good as new. NZ is 3.6ft gauge.
Someone send this to Vin Diesel so we can get Fast and Furious 11: Multi-Track Drift.
The entire video in short: they added small sets of wheels for more traction
There is one way extra traction can be obtained without the complexity of a small donkey engine, you take drive off an engine,s rearmost coupled axle via an upside down top loader spiral bevel spur gearbox on said axle. A prop shaft runs in a heat shield under the firebox to a second bevel gearbox on the trailing truck axle. With steam shut off, via lever in the cab, driver engages a dog or multi disc Heleshaw clutch on the trailing truck axle gearbox, like an old Willy,s Jeep. Once the train reaches 25 mph the booster clutch is disengaged, a lot simpler and lighter.
At that point there seems little reason to disengage it tbh - why not just keep the additional drive all the time? You'd need to size up the cylinders to provide the extra tractive effort, but you'd end up with a loco with more driven axles that can still go round corners, and arguably no heavier or more complex than providing a separate booster. The slightly bigger and heavier motion might be a small drawback at higher speeds, but big and fast locos were built successfully. I like it.
Maybe clearance under the firebox would be a limitation... although perhaps you could have a split ashpan with a transmission tunnel through the middle?
@@jonh845 You mean permanent drive to the trailing truck axle ,like a Range Rover or Audi Quattro?, that would help when climbing steep grades with a twelve or thirteen bogie coach train behind the tender. Oliver Bullieds 'Spam Cans' were notorious for slipping, so a permanently driven trailing truck axle is a no brainer.
@@basiltaylor8910 Arguably more like a 4Motion Golf ;-) Would require careful matching of gear ratio and wheel diameter though - tricky as the tyres wear particularly with different nominal sizes. Or you have to use something like a viscous coupling, which feels out of reach of early 1900s technology. Can't use a differential without basically moving to a complete geared drive like a Shay or Heisler.
@@jonh845 Er no , am talking the 1930,s when Dr Henri Foettinger pioneered a compact fluid coupling for Mercedes Daimler Benz, this coupling compensates for wear in tyres of different diameters by slipping just enough and not heat up the oil.
It’s Norfork and Western …..
Booster? I hardly know her.
At that time, the norfolk and WESTERN hadnt merged with the SOUTHERN railroad. That wouldnt happen until the late 80s to early 90s, making the norfolk southern.
I have a concept that would have worked well for the LNER and southern railway
Oddly enough, American railroads had no problems with boosters. What was wrong with Britain?
Bavarian 1400 is what AI uses as a reference for most steam locomotive pictures.
1:54 So would that be a 2-6-2 or a 2-4-2-2?
Or a 2-4/6-2?
I think 2-4-2-2 is probably the best one...
@@AnimeSunglassesOr maybe 2-4/2-2?
@@G-Forces that would have to be written 2-4+2-2...
But also then you have to pronounce the +...
@@AnimeSunglasses Oh yeah that is kind of a awkward to say...
@@G-Forces yep... Unwritten rules of English: extra syllables are expensive
Fun fact! There is a steam locomotive in the United States that is being restored to operation that has a booster. Boston and Maine railroad No. 3713 "The constitution" is being restored at Steam Town in scranton pennsylvania. Once restored, the locomotive will pull trains for the museum, and according to photos and articles I've seen and read, the booster on the locomotive has been restored and will be put on the locomotive for use. However, this booster is located on the tender, not the locomotive itself. Here is a link to a video on the booster. ua-cam.com/video/4Szhi0BV6N4/v-deo.htmlsi=lOQ0VjyVw0viPuHI
Odd choice when all they needed to do was lift the weight off the idler rail wheels.
so how is it that the Americans had a good run with boosters, case in point the Lima GS series of locomotive the Southern Pacific ran like the GS 4's one of which is still running all over the US as a tour locomotive. It has a rear truck booster system, and like other models of locomotives purportedly worked very well.
0:50 Correction: Wheels do not do anything to the tractive effort of a locomotive, they change the adhesion. And it's not exclusively the wheels either, it's how far the connecting rods are from the center of the wheel. If they are more than halfway, the engine will have more power at the cost of speed, and vice versa. What primarily changes the tractive effort is the cylinders and the boiler pressure. Faster locomotives have larger wheels so the cylinders don't have to work as hard at higher speeds. Get your facts straight man, 'cause despite what you say, people will take your word as gospel.
Wheel diameter does have an effect on tractive effort. The basic formula for tractive effort is: TE = (d * d * S * P)/D, where d is the diameter of the cylinders, S is the length of the stroke of the cylinder, P is the steam pressure in the cylinder, and D is the diameter of the driving wheels. So increasing the diameter of the driving wheels will have the result of reducing the tractive effort of the locomotive.
I realize I phrased this incorrectly. As you said, they do affect tractive effort. I more so meant to say that they are not the sole factor in tractive effort, but re-reading it I did say that they do nothing. Thank you correcting me!
It happens to all of us. The host should have also been more careful in his description of the power of steam locomotives.
3:58
It’s “Norfolk & Western”, not to be confused with its modern day successor “Norfolk Southern”.
Engerth-Locomotive
It's all about where the reverser is, if the reverser is all the way foward you are getting the most power, the closer you bring it to center the faster you go.
yay ja 1271 is in the vid
And what if we use it all the way not just when starting ? EH ?