A collision occurred on 2 December 1999 at Glenbrook in the Blue Mountains, west of Sydney, Australia, between two passenger trains travelling in the same direction. An inter-urban train from the Blue Mountains to Sydney collided with the rear of an interstate train, the Indian Pacific, designated WL2, which had been waiting at Signal 40.8 which was showing "halt", and was starting to move off. The interurban train designated W534 had just passed signal 41.6, some 1.1 km before signal 40.8, after receiving clearance from the signaller to proceed, for it was showing "halt". The interurban train driver accelerated to 50 kph in the block 1 , and only saw the rear of the Indian Pacific a short distance before the collision. There had been a failure of a power supply to part of the track-circuit system sometime between 08:01 and 08:04, when the Indian Pacific interstate train arrived at signal 41.6 at Glenbrook. Both signal 41.6 and its following signal, 40.8, showed "halt" (the fail-safe position, instigated by the track-circuit system failure). The Indian Pacific waited at 41.6 for about 7 minutes, first to wait for it to change, and then for the driver to contact the signaller (at Penrith) to obtain permission to proceed through the signal while it still showed "halt". The Indian Pacific driver was required to use the track-side telephone to contact the signaller and obtain permission to proceed. The telephone box was, however, locked (unusually) and the driver returned to his cab to get the key, unlocked the box, and received permission from the signaller to proceed. He then proceeded with "extreme caution", as regulations required, through the block to signal 40.8, also showing "halt". He took 7 minutes 45 seconds to proceed through the block, whose length from 41.6 to 40.8 was approximately 1.1 km, and halted at 40.8. His attempts to contact the Penrith signaller using the trackside telephone failed. He waited one minute, as required, and 1 I use "block" to designate the track between adjacent home signals. The Special Commission noted some terminological difficulties in describing such sections of track (First Interim Report, pp26-7).