Report 01/2020: Serious operational irregularity at Balham

Serious operational irregularity at Balham, 20 April 2019.



At around 19:05 hrs on Saturday 20 April 2019, a tamper, a self-propelled piece of on- track machinery, made an unsignalled and unauthorised move of about 600 metres, passing over Balham Junction, and entering platform 3 at Balham station, south London. The tamper could potentially have collided with a passenger train, which had travelled over the same junction in the opposite direction around 75 seconds earlier. The tamper stopped in the station, when the on-board crew realised that it was in the wrong place. There was no damage or personal injury.

The incident happened at the boundary of an engineering possession, where lines were closed for maintenance purposes. The plans for train movements out of the possession required the tamper, which had been working on the down line, to be crossed over to the adjacent up line while it was still inside the area under possession, and leave the possession on the up line. The crossing over move did not take place, and the tamper left the possession on the wrong line.

This happened because the person in charge of the possession (PICOP) provided incomplete information about the position of the tamper; the tamper driver and conductor driver did not query the instructions provided by the PICOP; and two signallers did not query the instructions provided by another PICOP. The standard of safety critical communications was poor throughout, resulting in no party having a clear understanding of the location of the tamper or the actions to be taken, and Network Rail’s management of the PICOP role has been ineffective. Underlying factors were that the labour supplier which employed the PICOPs had not effectively managed its own policy on monitoring safety critical communications, and that Network Rail’s strategy for improving and maintaining the standard of safety critical communications within the rail industry has been ineffective, and has not changed the work force culture or secured the adoption of good practice in respect of communications with and between signallers and other operations staff.


RAIB has made four recommendations, all addressed to Network Rail. The first calls for a review of the company’s strategy for safety critical communications involving its staff and contractors, to address underlying cultural factors and embed the use of standard communication protocols within the railway industry. The second covers a review of the process of handovers between signallers, during and at the end of shifts, to produce a structure which will give the incoming signaller full awareness of all relevant information about the location and intended movement of trains. The third recommendation relates to the provision of a suitable working environment for PICOPs, and the fourth to a review of that role, including the competency requirements and ongoing professional management of PICOPs. Two learning points relate to the need to test staff involved in safety incidents for drugs and alcohol, and the importance of not using mobile phones while driving road vehicles.

Response to recommendations:

  • RAIB will periodically update the status of recommendations as reported to us by the relevant safety authority or public body
  • RAIB may add comment, particularly if we have concerns regarding these responses.

RAIB Recommendation response for Balham

Published 3 February 2020