The 400 & 500 Class rail motors are a diesel trains built by New South Wales Government Railways (NSWGR) primarily for use on regional lines throughout NSW. The trains have since been phased out following a rationalisation of country branch line rail services in November 1983. The 400 Class power cars were built in 1938 at the NSWGR Carriage Workshops, Eveleigh, NSW, while the 500 Class trailer cars were built by Ritchie Brothers at Auburn, NSW.
The 400 Class power cars followed the same general lines as the Silver City Comet powers vans, although they were slightly shorter in length at 51 feet. They were fitted with two underfloor 150 horsepower Leyland Diesel in-line six-cylinder, petrol engines coupled to Leyland Lysholm-Smith hydraulic transmissions. This was a repeat of the installation used in the earlier Rail Motor No.38. No multiple unit capability was provided. Each power car was capable of hauling one or two trailer cars. The mechanical equipment was mounted underfloor and a passenger compartment seating 19 Second Class was provided at one end while the other was occupied by a large luggage compartment with a capacity of 4 tons.
FPH 404 was destroyed by fire at Narrandera in 1944 and the remaining three were fitted with diesel engines between 1953 and 1957. They were fitted with two 150 horsepower GM Detroit Diesel 6/71 in-line six-cylinder, diesel engines and Twin Disc hydraulic torque converter transmissions.
When built, the power cars had a toilet located in the front opposite the driver and the front window was covered by a metal plate which gave the driver limited vision at level crossings. The cars had a 'one-eyed' appearance and this earned them the nickname 'Lord Nelson'. The toilet was later moved to the rear of the passenger compartment and replaced by passenger seating.
402 was modified in 1972 with the installation of compartment seating eight First Class and a toilet at the opposite end to the main passenger compartment and coded HPC. It was planned to extend this modification to 401 and 403 but with the decline in passenger numbers, it was considered too expensive to be repeated. The others simply had four seats in the main compartment allocated to First Class.
With the decline in branch line patronage, the use of trailers became rare and some were reassigned to Sydney for suburban working, while those remaining in the country received little use.
The 500 Class trailer cars were the same as those used on the Silver City Comet except that air-conditioning was not provided. The cars had two basic configurations, a composite sitting car (CT 501-504 and 506) and a Second Class sitting car with (FT 505, 507 and 508). These last three were stored on completion in 1938 and finally entered service between 1941 and 1944. The trailer cars were initially delivered from the builder with Comet trailer numbers (213-220) but were renumbered into the 500 series before entering service. FT 505 was sent to Sydney to work with 42-Foot rail motors in 1951. The end doors were sealed and CPH operating equipment fitted. From 1951 onwards 501, 502, 504, 507 and 508 were fitted with a luggage compartment and coded as HCT. FT 506 and HCT 501 were later sent to Sydney and modified to work with CPH rail motors along the same lines as FT 505.