On Wednesday, 15 March 2000, at approximately 1928 hours, Train 2139, a diesel multiple unit passenger service, suffered a partial brake failure while descending the grade from Newmarket to Auckland. A permanent 25 km/h speed restriction on curved track approaching the station was negotiated at about 45 km/h before the service came to a stop some 40 m past its normal stopping place.
The partial brake failure was caused by a combination of a broken air pipe and a seized air valve.
A safety issue identified was the ability of brake efficiency tests to identify triple-valve defects. Tranz Rail took action to address the safety issue, and no recommendations were made arising from this investigation
