Was a Mark 4 set taken to Doncaster via Worksop yesterday? I was out for a walk with my family and at about 14:50 was near to the Sheffield to Lincoln line, specifically the bridge where the curve joins from the ECML. I heard the screeching of train wheels and wondered if it was a freight train as it sounded long. A quick check of Realtime Trains showed a Bounds Green to Doncaster working that had passed through platform 2 at about that time:
Realtime Trains provides live realtime running information for the Great British railway network using open data.
www.realtimetrains.co.uk
I then reached the bridge, next to the East Retford Rugby Union Football Club, and could just make out what looked like a Mark 4 DVT with a battery tail lamp attached in the distance. If that is what it was, it must have diverted via Worksop as it did end up at Doncaster as planned. If I had been a couple of minutes earlier I would have been able to have a proper look but I had no idea it was due through until I heard it.