KiwiRail has accepted four urgent recommendations for Wellington's commuter train network to stop further collisions.
The Transport Accident Investigation Commission on Thursday released its interim report into an incident in May this year where a train hit a stop block at Lower Hutt's Melling Station, injuring two passengers.
The train driver told passengers just before the crash that the brakes had failed and they should prepare for impact.
Deputy Chief Commissioner Helen Cull, QC, said on Thursday that investigators can't yet tell whether the train's braking system worked properly on the day of the accident.
But the Rail and Maritime Transport Union's general secretary, Wayne Butson, said on Thursday that drivers have long held concerns over the braking system on the Matangi trains, which run on the Melling line, and there have been numerous reports of braking system irregularities.
Mr Butson told Radio New Zealand's Checkpoint programme KiwiRail needs to improve the braking system to restore confidence among drivers that they work when they should.
Mr Butson said at two meetings on Thursday drivers spoke of their fears about faults with the system. They suggested that a switch be installed, so that in the event of problems they can use an alternative, proven braking system.
KiwiRail also needs to introduce safer approach speeds and proper buffer stops and should do weekly brake efficiency checks, he said.
The TAIC report recommended urgent changes on Wellington's commuter train network to stop further collisions:
- Restricting speeds at Melling Station
- Restricting speeds at similar terminals
- Upgrading stop blocks to better absorb collisions
- Shifting any poles carrying overhead wires from behind the end of rail lines
KiwiRail says it has already cut the speed limit to 25km/h for the approach to Melling Station and says there's nothing wrong with the braking system.
Helen Cull said slippery conditions and the adequacy of driver training are also possible factors in the crash.
Cannabis found in driver's system
The driver was found to have the active ingredient for cannabis in his system, the TAIC report shows, which Helen Cull said was consistent with him smoking a cannabis cigarette two to three days earlier.
However, she said it was yet to be determined whether the driver was impaired by the cannabis use.
KiwiRail said its drug testing regime is sufficient. General manager for passengers Deborah Hume said the rate of drivers testing positive for drug and alcohol use is lower than the rest of the world.
Ms Hume said the driver had been immediately stood down after the crash and is no longer working for the company. "What we always do after an incident is do the testing but also stand down the staff. I can confirm for you that he's no longer working for KiwiRail."
KiwiRail carried out 950 random drug tests in the past year, of which 14 had come back positive, she said.