CONTAMINATION OF the railhead and a vulnerable wheel-rail interface led to an incident in which the barriers at Norwich Road level crossing rose as a train approached, the Rail Accident Investigation Branch has concluded.
The incident occurred on the evening of 24 November 2019 at the crossing at New Rackheath, on the Norwich to Sheringham line. Greater Anglia’s Stadler bi-mode No 755416, operating the 19.45 Norwich to Sheringham service, was approaching the crossing at around 45mph. Around 150 metres away from the crossing, an instructor driver (supervising a trainee) noticed the barriers at the crossing rising, and instructed the driver to apply the emergency brake and sound the horn. Just before the train reached the crossing the barrier closure sequence restarted, but the train missed the rear of a vehicle crossing the line by less than half a second before stopping around 230 metres beyond the crossing.
The level crossing predictors installed on the line are HXP3 predictor units, which detect approaching trains using electrical contact, and the line was the pilot installation for the type on the UK network. A ‘loss of shunt’ (LOS) timer is initiated to prevent the ending of the crossing closure sequence in the event of a detection fault, and at Norwich Road this was set to 16 seconds, the default setting when delivered, lower than both the maximum available for the HXP3 (99 seconds) and the recommended level (120 seconds). RAIB notes there were right-side failures at Norwich Road crossing the day before the incident and at nearby Rackheath Road level crossing on 1 December, and in both cases the barriers failed to rise after a train had passed.