In Pictures: Potters Bar train crash

Images from Potters Bar railway station in Hertfordshire where a passenger train travelling from London to Norfolk has crashed.

One carriage was derailed onto the platform

Engineers are trying to work out what caused the crash

Police have shielded part of the crash scene with a tent

A waiting room was demolished in the accident

Crash debris fell from a bridge onto the road below

Potters Bar is a few miles from Hatfield where four people died in a train crash two years ago