Page:ATSB RO-2018-004 - Collision of passenger train A42 with buffer stop.pdf/8

 dynamic braking with brake cylinder pressure at zero, was decelerating slowly (~0.2 m/s$2$) as it travelled the approximate 168 m-length of Richmond Station.

The driver stated that when he regained his senses he reacted by applying the emergency brake. At 0951:28.1, the power / brake control handle was moved to the maximum brake position. There had been no control system input by the driver since 0951:06.1, 22 seconds before. The train’s speed at this point was 36 km/h and the distance to the buffer stop was 27 m.

It was approximately a car length before the buffer stop that the guard realised there was a problem. This would have given him less than 2 seconds to activate the emergency brake, which meant that even if it was activated, the train would have still collided with the buffer stop. There were no early clues to alert the guard that there was a problem with the driver. The train had entered the platform at a normal approach speed and the train was decelerating slightly. In this situation, the investigation determined that there was insufficient time for the guard to react by applying the emergency brake in his compartment.

At 0951:29.5, the driver moved the power/brake control handle to emergency. The train’s speed at this point was 34 km/h and the distance to the buffer stop was 17 m.

The first indication of the impact with the buffer stop is at 0951.31.1, when the Emergency Door Release Terminal Door Seal was recorded as having opened. This is the emergency door at the front of the train, which opens to the driver’s compartment. The train’s speed at impact was 26 km/h. The buffer stop stopped the progress of A42 and the impact sent a high deceleration shock pulse down the train.

After the impact with the buffer stop, the front of the train came to rest approximately 3 m from the buffer stop and the rear carriages recoiled further due to the partial recovery of the energy absorption elements that are distributed throughout the train. The impact caused all cars to concertina together, with some wheels lifting from the track. A post-incident inspection found, on the rear wheelset of the rear bogie on the third position car one wheel suspended above the rail, the other wheel derailed and all wheels of the rear bogie (No.1 end) on the fifth position car derailed.

There was damage to the front of the train, particularly the head of the Sharfenberg coupler (No.2 end of motor driving carriage D6342), the lower section of the front nose cone and the undercarriage. There was significant damage to the interconnecting areas between cars, the associated door systems and the coupling systems between cars. There was no visible damage to the interior of the driver’s cab or to the internal passenger saloon areas. The emergency door at the front of the train had become ajar during of the collision. The exterior stainless steel skin of the carriages, apart from the areas between carriages, sustained no visible damage. All carriage windows and exterior doors were undamaged. The exterior doors and opening systems were all functioning following the collision.

The collision caused substantial damage to the end-of-track buffer stop with a significant transverse crack opening at the corner of the base and the upright. The two hydro-pneumatic rams positioned on the front of the buffer stop also sustained damage (Figure 3).