Diesel Electric railmotor (VR)

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Diesel Electric Rail Motor (DERM)
Restored Vintage 'DERM' Rail motor runs a Rail Fan trip to Mernda, Melbourne.png
Preserved 58RM passes through West Richmond on a heritage trip to Mernda
Type and origin
Power typeDiesel engine, Originally Petrol
DesignerElectro-Motive Corporation
BuilderNewport Workshops
Build date1928–1931
Total produced10
Gauge5 ft 3 in (1,600 mm)
Length58 ft (18 m)
Loco weight43.07 long tons (43.76 t; 48.24 short tons)
Fuel typeOriginally Petrol, converted to Diesel fuel
Fuel capacity750 litres (200 US gal)
Engine type220 hp Winton six-cylinder petrol engine (Petrol)
2 x Series 71 twin six-cylinder diesel engines (Diesel)
GeneratorGeneral Electric DT 501E2
Traction motors2 x General Electric GE 273A
Performance figures
Maximum speed100 kilometres per hour (60 mph)
Power output220 hp (Petrol), 255 bhp (Diesel)
OperatorsVictorian Railways, V/Line
Number in class10
Numbers55RM - 64RM
First run1928
RM 63 as restored by DSCR in 2007
RM 55 as a PERM pre 1952
RM 58 Passes Thornbury on DERMPAV's Outer Suburban Tour 2022

The Diesel Electric Rail Motor (DERM) was a railmotor operated by the Victorian Railways of Australia.


Originally built as a petrol electric rail motor (PERM), they were the longest-lived rail motor on the Victorian Railways, with the first entering service in 1928 and the last being withdrawn in 1991.

The rail motor was a standard product of the US Electro-Motive Corporation (a predecessor of Electro-Motive Diesel) and built between 1924 and 1932,[1][2] albeit to a smaller loading gauge and wider track gauge. The first was imported in 1927, assembled at Newport Workshops, and placed in service in 1928.[2][3] The bodies of the remaining nine were constructed at Newport Workshops using imported equipment and electrical equipment and placed in service between 1930 and 1931.[2][3]

The rail motors were initially powered by a 220 hp (160 kW) Winton Motor Carriage Company petrol engine, until these wore out and were replaced in the 1950s by twin GM Detroit Diesel Series 71 engines, with a power output of 275 bhp (205 kW), derated to match the original 220 hp (160 kW) generator.[2]

A DERM, with a DERM Trailer car attached, ran a regular passenger service on the South Gippsland line in the 1960s and 1970s. By the 1970s, the longest scheduled journey run by a DERM was the Bendigo to Robinvale run, last operated on 3 June 1978.[4]

In 1976, RM 56 was fitted with a new seating arrangement, including rotating seats, using components from the Z carriage fleet. Capacity was reduced to 34 passengers, because the new seating arrangement was two either side of the central aisle rather than the previous two and three. The first-class end of the vehicle was moved towards the centre, closer to the engine, but providing a smoother ride by averaging the suspension of both bogies rather than just one.[5] The trial arrangement was used on the Yarrawonga line, but patronage did not increase sufficiently to justify the retention of that service.[6]

Following the changes to 56RM, 55RM and 61RM were extensively modified in the late 1970s, with the engines relocated, the body extended, and a new seating arrangement provided.[7][8] The most obvious external difference was the fitting of aluminium-framed windows on the driver's cabin, and porthole windows for the engine room.[9][10] These "Super DERMs" were a familiar sight on the adjoining Mornington and Stony Point lines prior to the early 1980s.[citation needed]

Details of vehicles[edit]

Motor units[edit]

Railmotor[11] Entered service Upgraded to DERM Withdrawn Current owner Current allocation Current status Notes
55RM "Super DERM" 1928-03-07 1952-10-27 1993 VicTrack Heritage Allocated to Yarra Valley Railway[12][13] Under Restoration "Super DERM"; formerly at South Gippsland Railway
56RM 1930-03-29 1952-08-29 VicTrack Heritage Steamrail Victoria, Ballarat Pending restoration Upgraded interior pre Super DERM program
57RM 1930-04-16 1952-12-30 1982 Scrapped
58RM 1930-05-03 1952-05-10 VicTrack Heritage Allocated to Diesel Electric Rail Motor Preservation Association of Victoria Preserved; operational
59RM 1930-05-14 1953-05-23 Diesel Electric Rail Motor Preservation Association of Victoria Diesel Electric Rail Motor Preservation Association of Victoria Supply of spare parts Formerly with Mornington Railway, transferred September 2015
60RM 1930-06-18 1951-10-29 Diesel Electric Rail Motor Preservation Association of Victoria Diesel Electric Rail Motor Preservation Association of Victoria Pending restoration Stored at Newport Workshops
61RM "Super DERM" 1930-06-21 1953-10-29 1978 Victorian Goldfields Railway Victorian Goldfields Railway Preserved; operational "Super DERM"
62RM 1930-07-21 1952-01-26 Daylesford Spa Country Railway Daylesford Spa Country Railway Stored; Pending restoration
63RM 1930-08-07 1952-12-06 Daylesford Spa Country Railway Daylesford Spa Country Railway Preserved; operational
64RM 1931-04-27 1952-07-26 Diesel Electric Rail Motor Preservation Association of Victoria Diesel Electric Rail Motor Preservation Association of Victoria Under restoration


Motor Trailer 29 in 1982
Railmotor Entered service Withdrawn Scrapped Current status Notes
26MT 1930-04-29 1982-11-16 Preserved - Stored? Daylesford Spa Country Railway
27MT 1930-04-29 1982-11-19
28MT 1930-10-04 1981-06-09 1981-08-17
29MT 1930-09-26 1982-11-19
30MT 1930-09-26 1982-11-19
Diagram of VR Railmotors


All but one of the DERMs have survived into preservation, with 57RM being the only DERM to have been scrapped. Four are operational, with the remaining five in various conditions, generally as a source of spare parts with long-term restoration in mind.

Of the regular DERMs, 58RM regularly runs tours on the Melbourne and Victorian broad gauge system, operated by the Diesel Electric Rail Motor Preservation Association of Victoria,[14] and 63RM runs trips on the Daylesford line with trailer 26MT when appropriate.[15]

55RM is allocated to the Australian Railway Historical Society Museum but was sub-allocated to the South Gippsland Railway. When the latter closed in 2016, it moved to the Yarra Valley Tourist Railway.[12] 61RM operates on the Victorian Goldfields Railway between Maldon and Castlemaine.[16]

See also[edit]


  1. ^ White, John (1978). The American Railroad Passenger Car. Baltimore: The Johns Hopkins University Press. pp. 606–7. ISBN 0-8018-1965-2.
  2. ^ a b c d Venn, Michael. "The doodlebugs that endured". Trains (April 1978): 45.
  3. ^ a b Victorian Railways Rolling Stock, 1926-1961. Victorian Model Railway Society. 1986. p. 150. ISBN 0-9596202-2-2.
  4. ^ Banger, Chris (March 1997). "Rail Passenger Service Withdrawals Since 1960". Newsrail. Australian Railway Historical Society (Victorian Division). 25 (3): 77–82.
  5. ^ Diagram D-4, 7 October 1976, available at http://www.victorianrailways.net/motive%20power/diagrams/dermdia.jpg
  6. ^ "Possible candidates for reopened country services in Vic?".
  7. ^ Bray, Vincent & Gregory, Preserved Rolling Stock of Victoria, 2013, ISBN 978-0-9806806-4-5, p.62
  8. ^ "Surviving EMC Railcars".
  9. ^ "55RM". DERMPAV. Retrieved 28 June 2017.
  10. ^ "61RM". DERMPAV. Retrieved 28 June 2017.
  11. ^ "Surviving E.M.C. Railcars - DERMPAV". DERMPAV.net.au. Retrieved 1 November 2016.
  12. ^ a b https://www.facebook.com/YarraValleyRailway/photos/a.291974420901885.59883.291969427569051/1115703191862333/?type=3&comment_id=1117184121714240&comment_tracking=%7B%22tn%22%3A%22R1%22%7D[self-published source?]
  13. ^ http://www.yvr.org.au/rm55-has-a-new-home-at-the-yvr/
  14. ^ http://www.dermpav.net.au/
  15. ^ http://www.dscr.com.au/
  16. ^ "Victorian Goldfields Railway".