As seen on MeFi:
This happened on the London Underground in 2007: a signalling failure resulted into a train being routed into the wrong branch of the Northern Line when entering Camden Town, so the signaller did the same with the next train and told the driver and passengers to swap trains. This worked, except that one of the drivers got in the wrong end of the train and drove off in the wrong direction.
From the linked investigation:
London Underground Ltd (LUL) have taken action to prevent similar incidents, including additional staff training and changes to operational procedures. They have also improved the reliability of train regulation equipment which controls the routing of trains.
RAIB has made four recommendations to address causal and contributory factors. These concern:
- installation of warning signs at Camden Town
- instructions for drivers when they leave a cab of a train to be replaced by driver
- recording technical interventions in the control room
- familiarity induction to stations where drivers may be required to change platforms between trains.