London Underground to investigate runaway tube train

LU said in a statement that at around 5.25am an engineering train performing rail maintenance became defective as it approached Archway station. The train was travelling southbound on the High Barnet branch of the Northern Line.

Engineers began to move the defective train northbound by attaching it to an out-of-service Northern Line train. 

For reasons that are now under investigation, at around 6.44am the engineering train became detached from the out-of-service Northern Line train and began to move southbound.

LU staff diverted passenger trains to the City branch of the Northern Line while directing the engineering train to the Charing Cross branch. Passenger services on the Charing Cross branch of the Northern Line were then suspended.

The engineering train eventually came to a halt at Warren Street station on the Charing Cross branch of the Northern Line at 6.57am.

LU director Richard Parry said: ’Safety is London Underground’s top priority, and we have of course launched an immediate and thorough investigation into this incident to establish the cause.