In pictures: Potters Bar investigation

Engineers have lifted the carriage which became wedged on Potters Bar station in Friday's fatal crash. HSE investigators are continuing to examine the faulty points which caused the accident.

Personal messages from survivors have been placed at the scene

The rear carriage became wedged under the canopy of the station roof

Engineers have spent several days propping up the train ready for lifting

The rescue operation must drag the carriage away from the canopy

Use of the 1,000-ton crane to lift the 35-ton train was delayed by poor weather on Monday

The recovery operation will last several days

Engineers covered the points at the centre of the investigation

A set of the train's wheels became detached in the crash

Three of the four train carriages derailed

A crane is installed to remove the carriage from the platform