Delays on the Line

This is the train that I was expecting to take me from Whitechapel to Mile End on a short and normally trouble-free leg of my journey home. Instead, after a ten-minute wait, the train pulled into the platform and immediately divested itself of all passengers, going (as it says) out of service.

There followed quarter of an hour of (as best I could tell) attempting to reverse the train into sidings, before the train crew gave up and coaxed it out of the station forwards. I'm now on a following train that's both packed and running slow as a result.