The Rail Accident Investigation Branch (RAIB) issued an urgent Safety Digest on August 18, following the derailment of a Class 165 diesel multiple unit at Paddington on June 16 (RAIL 804).
The RAIB is reminding railway operators of the importance of drivers using the resources available to them to refresh knowledge of track layouts and signals that they do not drive over regularly, as well as assessing the risk of using trap points to protect lines and why assessments should include examination of the potential consequences of derailing.
It also says drivers should be alert to the possibility that when a position light signal is cleared, the route may only be set as far as another position light signal rather than to a main signal or buffer stops, and that it is important signallers comply with any local instructions applicable to clearing position light signals when a route cannot be set all the way to a main signal or buffer stops.
The train involved was an empty stock working (3H52) that was planned to couple to a train at Platform 1 to strengthen the service. It was being held in Royal Oak sidings along with the other unit that would form the train (5H52).
The former was switched to strengthen the 1818 Paddington to Oxford rather than the 1812 to Henley-on-Thames. The signaller routed train 5H52 to signal SN6004 to clear space in the sidings for another empty stock train. The short-formed 5H52 was then routed into Platform 1 to become 1H52.
The driver of 3H52 was instructed to wait in the sidings until 1H52 had departed from Platform 1. At 1811 the route was set for 1H52 to depart. A minute later, the signaller cleared ground position light signal SN6006 for 3H52 to leave the siding. The signal authorised the train to run as far as a similar signal (SN6004), placing it in a position to run into Platform 1 as soon as 1H52 had cleared its section.
- For more on this story, read RAIL 808, published on August 31.