Corrosion causes signal post to fall on Newbury railway track

Obstruction hit by train travelling at 110mph

CORROSION caused a signal post to fall across railway lines between Newbury and Newbury Racecourse in November, obstructing a track, before being struck by a train travelling at 110mph.

The accident, at 2.35pm on November 17 , was revealed in a recent Rail Accident Investigation Branch report, when the First Great Western (recently renamed Great Western Railway) high-speed train, from Truro to London Paddington, struck a set of junction indicators attached to the top of a signal.

The post – rusted through at the base – had collapsed and fallen across the railway line.

The train was travelling at the maximum speed (110mph).

The signal post completely obstructed one track and also partially obstructed a second, on which the train was travelling.

There were no injuries and the train did not derail, but the train’s exterior bodywork was damaged and an air pipe ruptured.

The outcome could have been more serious if the first train to encounter the collapsed signal had been travelling at speed on the completely obstructed track, according to the report.

The signal collapsed because the base of the hollow tubular steel post had corroded through, causing an almost complete loss of wall thickness at, and just above, ground level.

Corrosion had occurred to both internal and external surfaces; internally because water had entered the post, with no drainage from it, while the external corrosion was affected by the base being buried in ballast, which held water around the base and damaged its protective coating.

Despite annual examinations, the fault remained undetected because the main area of corrosion was hidden by ballast, and examinations did not extend to cover this possibility.

A separate examination in 2012 for a resignalling project in the area also failed to detect the defect, for similar reasons.

The RAIB has made five recommendations in its report, four of which were addressed to the owner and maintainer of the infrastructure, Network Rail, and which covered the management and examination of signal structures and their resistance to such failures.

The fifth recommendation was addressed to contractor Amey plc, the company that carries out structures examinations on behalf of Network Rail.

The RAIB also flagged up a general learning point from the incident, relating to visual examinations on structures such as signal posts.

A Network Rail spokesman said: “The safety of our network is of the utmost importance to us and we will take any steps necessary to prevent a recurrence of this incident.

“We will be studying the recommendations of the report in detail.”