NZR EO class (1923)

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New Zealand EO class (1923)
NZR EO class locomotive 05.JPG
EO 3 running around a train at the Ferrymead Heritage Park.
Type and origin
Power typeElectric
BuilderEnglish Electric
Dick Kerr Works, Preston, United Kingdom
Build date1922
 • UICBo-Bo
Gauge3 ft 6 in (1,067 mm)
Length11.7 metres (38 ft 5 in)
Adhesive weight50.0 tonnes (49.2 long tons; 55.1 short tons)
Loco weight50.0 tonnes (49.2 long tons; 55.1 short tons)
Electric system/s1500 V DC overhead lines
Current pickup(s)Pantograph
Traction motors4
Performance figures
Maximum speed64 km/h (40 mph)
Power output510 kW (680 hp)
Tractive effort63 kN (14,000 lbf)
OperatorsNew Zealand Railways
Number in class5
Numbers2 - 6
LocaleMidland Line between Otira and Arthurs Pass
First run4 August 1923
Last runApril 1968
Disposition4 scrapped
1 preserved

The New Zealand EO class of 1923 were electric locomotives used on the steep Otira to Arthurs Pass section of the Midland Line. They were primarily needed for pulling trains through the 1 in 33 grade 8.5 km (5.3 mi) Otira Tunnel which was too long and steep to allow steam locomotives to be used.


When the Otira tunnel was being built, steam locomotives were not considered for use in the tunnel, because smoke would build up in the tunnel and be difficult to clear. The English Electric Company, of London, won the contract to supply six electric locomotives, the installation of overhead contact wires, and the building of a coal-fired electric power station at Otira.[1] On 10 April 1923 six electric locomotives arrived, numbered E 2 to E 6 (1 was the Class E battery electric loco built in 1922). They were later reclassified Eo to avoid confusion with the EC class locomotives.[2]


The locomotives coped well in service, and from 1942 it became standard practice to run three locomotives together with only two pantographs up, and have their pantographs linked by jumper cables. This was deemed dangerous however, and soon each locomotive ran with its own pantograph up. This often resulted in heavy sparking. Once it became normal to run three locomotives together, they were altered in 1940 to a single cab design.

Another view of EO 3

Withdrawal and Preservation[edit]

The class were replaced in April 1968 by the EA locomotives (which were later re-designated as the EO class of 1968). All but one were scrapped.

EO 3 was preserved by the Canterbury Railway Society. The locomotive arrived at the Ferrymead Heritage Park in 1972 and was restored to operating order in 1977. The locomotive has had the removed cab restored to the original style and carries its original number E 3 on that end of the locomotive. The loco received a Restoration Award from the National Federation of Railway Societies in 1996 and today can be seen operating on the Ferrymead Railway.[3]

See also[edit]


  1. ^ Pickering, A.J. (1970). Pioneer Electrics: A survey of railway electrification in the South Island. Christchurch: The Tramway Historical Society Inc. pp. 7–8.
  2. ^ "Eo class of 1923". English Electric Railway Traction in New Zealand. 13 December 2016. Retrieved 15 December 2016.
  3. ^ "Electric Locomotives". Canterbury Railway Society. 2005. Retrieved 15 December 2016.

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