London Northwestern unit derailed on West Coast Main Line during unsignalled wrong direction move

A formal investigation is under way to understand how a train derailed on the West Coast Main Line.

The London Northwestern unit (350247) derailed on a switch diamond crossing at Denbigh Hall South Junction near Bletchley at 1227 on June 26. It was travelling at approximately 15mph at the time.

The Class 350 was one of two working the 0906 Birmingham New Street-London Euston when the service was terminated at Bletchley due to a unit failure.

The Rail Accident Investigation Branch (RAIB) said the unit could be driven north from Platform 4 but a failed on-track machine blocked the only signalled route in that direction from the Down slow.

The signalled route would have taken the train along Bletchley Relief Line 1, across the Up slow and onto the Down slow at Denbigh Hall South Junction.  

Because that line was blocked staff at Rugby Rail Operating Centre allowed a wrong direction movement along the Up slow until it could cross over to the Down slow.

“This wrong direction movement required the signaller to instruct the driver to pass the north end platform signal at danger and travel to Denbigh Hall South Junction without the protection normally afforded by the signalling interlocking,” a RAIB statement said.

“The intention was the train would then cross onto the down slow line at the junction and return it to normal signal control for its onward journey northwards to Kings Heath depot near Northampton.”

RAIL understands there is no way of crossing from the Up to the Down slow at Denbigh Hall South Junction – only from Bletchley Relief Line 1 to the Up slow.

It’s thought that once the Class 350s reached the junction it had been set to allow a train to cross from the relief line to the Up slow, and as a result the leading bogie of 350247 derailed.

The junction remained out of use until 1605 on June 29 while the train was recovered and track repaired. Damage to the points also led to trains being unable to join the West Coast Main Line from East West Rail as Denbigh Hall South Junction is also the point the two routes merge.

RAIB will look into the sequence of events and action of those involved, how out of course movements are determined and validated and the management of staff involved.

RAIB is also conducting a preliminary examination after an Avanti West Coast Pendolino hit the buffers at London Euston.

The 0652 Edinburgh-Euston service hit the buffers at Platform 1 on July 5.

Avanti West Coast said no injuries were sustained by passengers or crew.

RAIB inspectors are gathering evidence but are yet to make a decision on launching an investigation.