The Hitachi (also known as Martin & King or Stainless Steel) was an electric multiple unit that operated on the Melbourne suburban railway network between 1972 and 2014. Electrical equipment was supplied by Commonwealth Engineering to designs by Hitachi of Japan, leading to their official name today, though no actual Hitachi-supplied components were used in their construction. They were the last suburban trains in Melbourne with no air conditioning. A total of 355 carriages were built between 1972 and 1981, including a replacement carriage for one written off while the fleet was still being delivered. Configuration Based on a successful trial of longer Harris trailer cars built between 1967 and 1971, the Hitachi used carriages long, up from the standard length of the earlier suburban cars. The revised carriage design enabled a six car Hitachi to seat 560 passengers, up from 540 for a seven car Harris, and allowed a maximum load of 1,500 passengers, 300 more than a Harris. As delivered, Hitachi trains were composed of three types of carriage; driving motor, trailer and driving trailer; coded M, T and D respectively. These cars were arranged in sets of M-T-T-M and M-D, which could be arranged together to create a six car set. Early M and D carriages delivered were provided with nose doors at the front of the cab, which allowed passengers to move through them and between coupled units in a train. This feature did not last, as instructions were soon issued to lock the doors to cabs to prevent unauthorised access. The nose doors also tended to leak and cause draughts, and so the feature was omitted from later carriages, and the door was covered over in sets containing them. All but one of the 68 D carriages (353D, involved in a collision at Pakenham on 16 April 1980, that also resulted in the scrapping of guard's van Z286) produced were converted into T carriages by the late 1970s, in order to form symmetrical M-T-M units for the opening of the City Loop. These units could be doubled to make six car sets, configured as M-T-M-M-T-M, which became the de facto unit configuration in the 1990s, due to refurbishments. The 237 motor carriages that have been in service have been numbered 1M through 237M, and the 117 trailer carriages, 1901T through 2017T. On 15 August 2009, the remaining Hitachi carriages were renumbered in order to make