Cityrail 620/720 Railcars

The 620 & 720 class was a class of diesel regional branch line trains used between 1961 and 2007. The trains have since been phased out in favour of the newer Hunter railcar model.

Description
The 620/720 railcars were built by New South Wales Government Railways (NSWGR) from 1961 to 1968.

They were built with several different engines. Six of the power cars were originally fitted with two 250 horsepower Rolls-Royce engines coupled to automatic lock-up torque converters. The next 11 had two 250 horsepower General Motors engines. The last unit 638/738 was fitted with two 280 horsepower Cummins engines coupled to automatic lock-up torque converters. The reason why six of the cars had Rolls-Royce engines is unknown, but there is some evidence that Rolls-Royce had financial difficulties at the time, and so NSWGR may have obtained these engines at extremely low prices. One of the Rolls Royce power cars was retrofitted with a General Motors engine after being damaged in a fire.

By the mid 1970s, the engines and transmissions were starting to experience mechanical issues. To keep sets working, a set with one engine inoperative was often coupled to another set with the same problem. At the same time, Cummins engines had been ordered to replace the ones on the 600/700 class railcars. As the 620 class engines were in worse condition, some of these engines were used to replace failed 620 class engines.

Straight air brakes with a special emergency feature and miniature automatic couplings were fitted as standard equipment.

The Department of Railways' Water Supply Workshops at Chullora gained experience in lightweight bodywork whilst building aircraft during World War 2. Consequently, these and all other in-house DMUs featured bodywork of largely aluminium composition. Whilst such bodywork is light and relatively strong, the NSW DMUs are considerably less crashworthy than contemporary steel and stainless steel coaches. However, this less-than-crashworthy characteristic is typical of early railcars, including those built by British Railways during the same period. These railcars operated in two car sets, with one driving motor car (620 class) and one driving trailer car (720 class). They were non-airconditioned, instead having opening windows, fans and gas heaters. The cars retain an interior similar to the 1960s setup with which they were delivered, with older seats still having the NSWGR markings. In the later period before they were withdrawn, elements were introduced to prevent windows being opened widely (and body parts protruded) and the exit doors from being opened mid journey. Prior to this, doors were frequently opened for ventilation.

There were also several different interior configurations on this train, as detailed in the table below. The first five sets were intended for short suburban journeys and configured as. The next six sets were intended for outer suburban services and were configured as NPF-NTC. The next two sets were intended for intercity services and were configured GPF-GTC. The next 4 sets were intended for country services and were configured HFP-GTC. The last set was intended for the Grafton-Murwillumbah line and was configured MPF-GTC.

In Service
The trains were used on various lines, as detailed in the table below. As newer trains were built, the 620/720 railcars were increasingly moved to suburban operations. All power cars were converted to the MPF configuration and sets recoded NPF-NTF.

All sets were withdrawn in 2007, due to the introduction of the Hunter railcars, with the last service running on October 29 from Newcastle to Paterson and return. Only a hand few were preserved. Set 621/721 was subsequently allocated to The Rail Motor Society at Paterson which have been restored to operational condition in the Indian red colour scheme, whilst set 623/723 was allocated to the NSWRTM as a static display. Others are in various collections in a non-operative state. 631/731 became RailCorp's Mechanised Track Patrol Vehicle, numbered ML070, however this car has also since been replaced as of 2014.