Why Do Metros Use Rubber Tires?
Вставка
- Опубліковано 21 сер 2024
- While most subway systems like the London Underground and the one in New York City use steel wheels, a few metro / subway systems in the world use rubber tires. Some examples include the Paris metro, Montreal metro and the Mexico City metro.
follow me: / roberthalpern_
Sources:
Steel reduces 85-99% of friction statistic - steelinterstat...
^^^ This source may not be reliable because they actually build steel rails.
Diagram of the track - emdx.org/rail/m...
McGill Uni. article (Great read) - www.mcgill.ca/...
Song: Great Day by Madvillain (Hopefully no copyright blocking issues)
#metro #railway #railfans
How can you say riis "a lot cheaper"?
They have to deploy the concrete roadbed AND rails if there's a flat tire. The roadbed is more complex with rails AND concrete running platform.
Rail only systems can be deployed in pre-fab sections and laid down quickly. These have to be poured in place.
You’re absolutely right, when writing the video I’m guessing I was acting as if the rubber wheeled trains were running on a regular concrete road (which would be cheaper than steel rails). I completely forgot to include the guide rails and the added costs of pouring concrete in a tougher way.
Thank you for the correction, I’ll pin this comment.
A very interesting point to note is that the Lyon Metro in France uses rubber wheels, with the exception of their line C. This line goes up very steep grades (a 17% incline), but uses steel wheels with a rack and cog, so I recommend building cog railway systems instead of rubber tire metros when it comes to steep grades and efficiency.
I didn't realize that the Paris metro used cogs at all, that's cool. Yeah I agree though, steel alternatives (like cogs) seem to just be better in the long run than rubber.
Lyon inherited a rack railway, and it was cheaper to retrofit it to metro standards instead of completely overhauling it to rubber tyred metro
@@robert.halpern Not Paris, Lyon.
Same in Paris. It’s pretty cool I like the trains even though they are a little outdated but like the style of it
the problem with rack railways is that they're very, very slow. seriously, the top speed for one i could find is 15mph (the montreal metro runs at 25mph uphill and 45mph flat), and looking at a video of the c line, the trains are seriously about as fast as a bicycle. that's not gonna cut it for actual mass transit along steep inclines, especially when you can drive a car up an even steeper hill faster. rubber tire metros work well for such applications, and while they are just glorified trolleybuses... what would anyone actually have against trolleybuses? i just think they shouldn't be relied upon when proper grade-separation and routing can allow for normal rail to be used instead.
now, if someone comes along with a way to improve rack systems to be used at higher speeds comparable to rubber, i'd be 100% on board.
There's something that you did not mention that's a big factor on why some cities choose rubber tires for their metros, and that's earthquakes. In both Mexico City and Santiago de Chile, for example, part of the reason to choose rubber was the intense earthquakes the cities suffer, as rubber bounces better (thus generally sustaining less damage and being less likely to de-rail), during an earthquake, or so I've been told. You can look up 'sismos en el metro cdmx' to see what I'm talking about.
In Santiago new steel wheeled lines are being constructed due to upgraded earthquake safety standards.
Both Japan nor California have shown little interest in rubber-tired trains, and northern Japan, in particular, suffers from frequent magnitude 6 earthquakes.
@@pacificostudios As I said, earthquakes are only one reason among many to be considered, there's lots of factors for why Japan or California might have decided they liked steel better; maybe with new safety standars the benefits of rubber in withstanding earthquakes have diminished recently or disappeared completely, maybe weather or prices or pre-existing infrastructure or maintenence requirements or just an aestethic preference or any onther number of factors influenced those choices.
But my comment was not to say that rubber tires are always better for earthquake-prone regions, just that at the time these choices were made, earthquakes were presented as one of the reasons for taking them.
Also, the way the vibrations of an earthquake look like change depending on a lot of stuff, so even if rubber tires used to be more helpful for some kinds of earthquakes, they may not be as useful for other kinds.
Edited for misspellings
In the case of Mexico city, it also is due to the sinkage of the soil, leading to a more stable ride on rubber wheel.
RM Transit made some good videos on this... Basically this was advantageous in 60s and 70s for metros with close stations and/or steep inclines, but nowadays with better technologies, rubber wheel train is only useful for extremely niche scenarios at best.
While I do have a weird penchant for the smell of rubber tires, I can't imagine most would fancy such smell...
Mhm, it does seem like steel is improving and is slowly making all the benefits of rubber tech obselete for trains.
I'm curious which RMTransit videos you saw, I watched his Paris metro explained video which was interesting but I want to see another video on it.
Thanks for the video, when i went to mexico city, i just wondered how did the circuit worked, because with conventional metros the supply current with third rail or ohle, goes in and then returns via the running rail, with the metro in mexico city, i didnt know how the circuit was completed, Its cool how a compressed shoe is pressed in the inner steel rails to return the current.
Two things, firstly they are not more quiet. And second, construction costs are not lower. The guideways contain the same old metal rail with all the rest of the components like tie plates, rail clips, etc... in addition to the concrete guideway for the rubber tires. There is a regular metal train wheel on the inside next to the tires. These are required for turnouts and in case there is a flat tire, as the metal wheels usually rides just above or making very light contact with the rail. The vehicles are more of a niche product that also contains extra components and complexity thus making them more expensive and require greater maintenance. You can get equally quick acceleration with lighter train cars and powerful motors with good slip control. (something BART has more or less done from day one, although arguably rainy days seem to argue against this) Also there is a compromise with adhesion and efficiency in the metal wheel profile (shape). BART uses a fairly flat wheel head which has a greater surface contact area giving them better acceleration and braking and stability at high speeds. (same basic profile as the Shinkansen) The tradeoff is a little more energy use and noise.
Sorry that this video took a while - was making the vid in very little spare time. Sources for the video are listed in the description, I used a lot of wikimedia commons photos as stock.
Curious to hear your thoughts on Rubber vs. Steel. As I said, I like steel more because it's much more sustainable and doesn't need as much energy once moving.
It’s okay, videos like this take a long time to make. A 1 minute video on my UA-cam channel took two weeks to make. This is a banger vid.
I liked this video, thanks for creating it. :]
Montreal, Paris , Mexico city AND SANITAIGO CHILE ;-)
Actually in Mexico City have a two lines with railroad wheels, the Line A and the infamous Line 12, one is short (A), and the other is long (12) as many other in the city (neumatic as 1, 2, 3, 7, 8, and B. This ones across all the city side by side; and the city is very long).
Actually I think it uses both.
It seems that tire trains have more disadvantages than advantages.
Rubber tire systems will never be more than a niche-use product. It's universally accepted that Steel is the only way to go today. Plus globally there are just far more companies and investment that has been pushed into the development of rail systems. So availability for parts, choice of customizations available, available competition for bids between manufacturers etc... are all far more plentiful than they are for rubber tire systems.
Plus you can have longer, larger, and heavier trains with a steel rail set up, than with tires. This just flat out means you can have a larger seating capacity per train as well as more space for legroom and headroom.
Tire-based systems have more disadvantages than they do advantages. Yes, more grip. But at higher speeds rail actually is quieter and again as a result of less friction, far more efficient. In addition to this, you can maintain higher speeds with steel wheels without having to worry about heat build-up or steel belt failure happening like in a tire.
Tires certainly have their place. They fit very specific situations very well. But for a train, steel is the only way to go for 99% of all cities. The tire-based systems that do exist today will likely be all that you really ever see as those specific cities need a niche-like product. Much like a Cog Railway is a very niche train purpose-built for a specific type of situation of climbing very steep grades. Again has it's place in the world. But it's not ideal for almost any other type of everyday situation. 🙂
Yep, but I guess this was not always the case. Simple truth about steel and rail tech is that they evolve so the shortcomings of steel earlier (less traction, worse acceleration etc) can be fixed over time. The same can be said for rubber and we will get rubber that can support heavier loads in the future but steel will probably be superior for the next couple of decades at the very least.
I'd love to ride a proper cog railway because I can imagine it would be completely unlike a normal train.
Thanks for taking the time to write that!
They are entirely more quiet than steel tires dude.
Have you been to Brooklyn before? I could not believe how loud the trains on the tracks were there.
Paris uses a combo of steel wheels and tires. It allowes the tires to be used on steep slopes and steel on other parts. The supporting ledge on wich the tires ride differ in height along the track allowing the traction to go from tire to steel and back, without mechanical intervention.
I agree to what you say except Stm has some machine that added a new layer of rubber when the threads of the tire finish so it can give a longer life than noisy Exxo trains
bro forget that Sapporo also have one.
Taipei, Taiwan also uses rubber tired trains on their Brown / Wenhu line
BANGER
Here's another interesting fact: The Montreal metro uses wooden brakes soaked in peanut oil. This is true even for the more recent Azur train sets.
This is underrated content
Singapore has these things called LRT (actual name is people movers ) they have rubber tires actually
Given the historical involvement of Michelin in early rubber-tired train designs, I suspect that French politics has played an inordinate role in the adoption of the technology. Every proposed advantage of the technology seems to come with a countering disadvantage. For example, reduced station spacing also reduces average speed while greatly increasing cost per mile, as stations are costly because they occupy valuable surface real estate. LRT can accommodate grades of at least 5%, which is as steep as a freeway.
I've noticed the rubber wheels on Montreal but never really thought much about it. How long will a rubber wheel last before it needs to be replaced, when compared to steel? I would think more often, but I also think a rubber wheel is cheaper than steel wheels, so the comparable costs will take some calculating. I also assume rubber metro tires are solid rubber, not something you inflate, so flat tires between metro stations isn't likely.
They definitely wear out more quickly than steel because rubber isn’t as good with heavy vehicles. High quality steel might cost more than rubber but rubber definitely isn’t cheap. $400+ * 8 wheels per car is a lot of money when it has to be replaced.
Not sure how it affects cost but most wheels on busses are about 50% rubber but 50% sulfur as well (My numbers might be wrong but it’s a big part of tires).
Search up sulfur vulcanization on google or Wikipedia, when making the video I used that to help research. I bet they have some special composition for truck / bus / train tires that will be most durable to prevent flats but there are safety measures in place to protect the train in case of a flat. One of the links in the description has a diagram of the bottom of the train and you can see they have an inner steel wheel that will lower and trigger a sensor with a flat. They have their systems but really steel is just less maintenance.
@@robert.halpern Thanks.
They last about 250 000 km. They are inflated at high pressure (10 bars instead of 2 in your car) with nitrogen instead of air while in a metallic cage to prevent injuries in case something goes wrong. In terms of overall cost, I don't think there is a significant penalty compared to steel.
Steel wheels + linear induction motors = the best of both worlds (and some)!
For the cost of tires in France when the first prototype of rubber tyre train has been built they had a collaboration to reduce cost of tyre.
I never even knew some metros have rubber tires😵💫💀
Fr. Prob cuz I really only pay attention to the MTA/NJT/AMTRAK
Steel wheels with linear motors could work quite well, since linear motors' acceleration isn't restricted by friction.
I live in Montréal and I've used metros in several cities around the world. I hate trains on tires. They're so loud! And they vibrate a lot more (you can't manufacture perfectly round tires (compared to machined steel wheels) and it gets even worse under load). But apart from the tire system, I love Montréal's métro.
In Mexico City we use rubber tires because they have less impact on our watered soil. We have two lines with steel wheels and both have a greater mantenience cost than the rubber ones due to track deformation.
That's interesting! Is Mexico City still affected by the former lake in other ways? I would imagine that construction of skyscrapers is impacted by the fill in job.
Thanks for the info, Apu!
Great video and great editing!
Why not do a hybrid? have traditional steel rails and steel wheels, they could be raised/lowered as needed, lower for acceleration, going up hill, downhill, and emergency braking, raise for coasting and pretty much everything else
To restate your comment, they could use traditional steel on steel rail to conserve energy lost from that friction from the rubber tires and just swap which one makes contact with the ground (or even have the traditional part permanently make contact with the rail and just lower/raise the rubber tire) but…… A) rubber is heavy… steel is also heavy. The energy saved by less friction might be lost by carrying that extra weight. B) anything that moves required expensive maintenance. It’s not even just swapping between third rail and overhead/catenary power, it’s completely redesigning the bottom of the train to somehow make space to raise and lower the tires.
Either way it would be more expensive than just keeping it simple. But most rubber tired metros use some form of steel rail anyway to guide so it’s really not that far off.
Sapporo’s metro system is similar to Montreal but it has some unique features.
Entirely enclosed elevated sections for one; it snows a lot in Hokkaido
Having lived in Montreal for about 2 months, I love rubber-tyred metros. The feeling of riding the Montreal metro can be described as a slightly out of control, bouncy roller coaster. It’s fast and furious and you get used to it.
As much as I wish NY’s subway was a thrill ride like Montreal’s, I don’t think everyone would agree to that. Speed here really depends on a stop to stop basis- some are great but there are some pretty slow intersections. I’ll guess Montreal doesn’t have the same problem with lines connecting and slowing each other down because they seem to each use their own tracks.
@@robert.halpern Meh the first couple of time I rode on the Montreal Metro it was really noticeable but after a couple rides, I got used to the bouncyness. The speed is indeed dependant on the station spacing however, I feel like in need to reemphasize how darn quick this trains are under acceleration. The traction is insane.
So a few wheels made of rubbr and the rest are nornal
I think hillier and earthquake prone cities chose rubber tire metros because rubber tire are more flexible and gripper.
Surprisingly engaging for a 500 subs channel, hope you get big
What we need is the massive adoption of passive maglev which the Chinese just recently added to their Skytrain suspended monorail system... It reduces energy and noise and obviously wear and tear on the guideway since none exists!
ua-cam.com/video/aXXY3f6itHw/v-deo.html
ua-cam.com/video/KZitDjn5TyU/v-deo.html
But it looks cool
While it's look cool, rubber tyred metro can cause everyone stress while riding because of rubber wheels instead of steel wheels.
Why can't train wheels be coated with solid nylon? Quiet, wears slower and 100% recyclable.
Think of skateboard wheels.
Um, that's not how rail wheels work. The surface contact area is so small that basically any other material than steel would be crushed.
uhh interesting
Montreal’s transit system actually has a retreading shop for the buses. Not sure if they also retread the metro. With buses they follow a strict protocol and only let the tires on the road for a limited amount of use before they are taken back to the shop. It’s better for the environment.
Really? Rubber wheels are quietter than steel? Personally i find trains to be way quietter than driving a car, but are metroes different?
yoo i also went to montreal during the summer and found it really interesting how their metro system has rubber tires and no a/c as well. hmm. but the new models felt pretty futuristic compared to what we have in NYC. this is really good insight
They had a reason for the lack of AC, something like since the metro was all underground it would heat up the tunnel. I agree about their new cars being much more modern than NY and I think they are still going to be more modern than the new R221 cars.
real men don't use rubber!
The Rubber Tyres on the Trains makes them look a bit Ugly compared to the Metal Wheels on Most Trains