Southern Service to Milton Keynes Central

A Southern Class 377/2 is arriving on a service to Milton Keynes Central coming from East Croydon. Milton Keynes Central is probably the furthest North a Southern service goes to. This particular morning, a lot of trains were cancelled so I was lucky to be on a Southern service that was running as normal. The other train to East Croydon was also running too, there was a signalling problem in the morning.