The Number 1 Railway Detective Agency


The curious case of the trains that did not bump at tea time.

Taken from the A406 Bridge this picture shows a District Line train on the line from Ealing Broadway to Hanger Lane Junction where it joins the Piccadilly line Uxbridge branch. Our thanks and copyright acknowledgements to Nigel Cox

We have commented in the past on the work of the Rail Accident Investigation Branch (RAIB).

In their latest publication they have examined, with typical diligence, a near-miss incident that took place at tea time on the 27th March 2009 at Hanger Lane between an eastbound District Line train from Ealing Broadway and a westbound Piccadilly Line train heading for Uxbridge.

Mercifully such incidents are rare. The last time the RAIB were called in to investigate a similar SPAD (Signal passed at danger) problem was in April 2006 at High Street Kensington.

As with many such incidents, a whole series of contributory factors blended together at Hanger Lane to form a potentially fatal cocktail.

A low spring sunset, reflecting off a signal lens, possibly caused a District Line Driver to misread a signal on the approach to the junction of the Piccadilly and District Lines at Hanger Lane Junction.

A signaller, with known health concerns, may have been distracted whilst manning the control desk for two colleagues on a meal break and feeling under pressure to get the system running to avoid major disruption to the evening peak services.

The 1950’s designed engineering with spring loaded trailing points and the positioning of insulated rail joints with respect to signals was adequate for all situations but this one.

Communications difficulties between the District and Piccadilly control rooms were compounded by a simultaneous incident at Sloane Square.

All these themes play their part in this story. There was an element of luck when a colleague in the control room realised the significance of what was going on and warned the signaller. This, and the 115 metres remaining when the District line driver saw the Piccadilly line train cross his path, meant that this incident was an inconvenience to and not a tragedy for passengers.

The RAIB are not in the blame game and their objective is ensuring that lessons are both drawn and learnt. All of their recommendations have been accepted and adopted by LUL and TfL. The report gives outsiders an insight into the pressures and responsibilities all LUL staff are obliged to bear as an everyday part of their duties.

Legendary golfer Gary Player was once asked why he was so lucky. He replied,“ The more I practice, the luckier I get.” As far as the RAIB are concerned, “The more we learn, the luckier we remain.”

Written by Mwmbwls