JNR Class ED72

JNR Class ED72
ED72 1 in November 2023
Technical specifications
Manufacturer(s)	Toshiba
Constructed	1961 – 1962
Number built	22
Classification	B-B
Dimensions	17,400 mm × 2,800 mm × 4,260 mm
Gauge	1,067 mm (3 ft 6 in)
Current collector	Pantograph
Electric system(s)	20 kV AC (60 Hz)
Traction system	Combination of high-voltage tap changers with mercury rectifier grid phase control and field weakening control
Service information
In service	1961 – 1982
Number in service	None
Fleet numbers	ED72 1 – ED72 22
Scrapped	1976, 1978 – 1982
Preservation information
Preserved	1
Number scrapped	21

The JNR Class ED72 is a Japanese AC electric locomotive operated by the Japanese National Railways from 1961 to 1982.

History

The ED72 was designed specifically for use on the Kagoshima Main Line due to the use of AC electrification on that line. The locomotives were specifically designed for use in Kyushu.

Twenty-two locomotives were built from 1961 to 1962; Toshiba manufactured both the electrical and mechanical components of the locomotives. Equipped with a steam generator, the locomotives were used on passenger trains which required onboard heating, as well as for pulling Blue Train sleeper trains, freight trains and towing other locomotives. Their axle load prevented them from entering other lines. The ED72s were withdrawn from pulling Blue Trains in 1968, being replaced by the ED73 in this regard.

Operation of passenger express trains would by this time be operated by mainly the ED76 locomotives in addition to a reduction of nightly express trains running to Honshu, so the ED72s were withdrawn from services. The locomotives were however returned to pulling Blue Train services, which now used 12 and 24 series passenger cars which did not require any special equipment on the locomotives to function. Withdrawals began in 1976, starting with ED72 1 and ED72 2; withdrawals for the rest of the class began in 1978, with all locomotives withdrawn by 1982. They were replaced by EF70 locomotives in these duties.

ED72 1, located at the Kyushu Railway History Museum, is the only preserved ED72.

Design

The ED72s featured large box-shaped bodies with a slight rake with dual large circular headlights mounted on the top of the cars.

Specifications

ED72 1 and 2 used a Quill drive system; MT103 traction motors were used on both locomotives. Mass production locomotives used a nose suspension drive system with MT52 traction motors; the use of the nose suspension drive was due to maintenance problems involving the Quill drive, so all locomotives after the earlier EF70 would use the nose suspension drive. This however came at the cost of keeping the rated rotation speed of the traction motors low.

Originally fitted with mercury rectifiers, these were changed to silicon rectifiers in 1970.

Preservation

The following Class ED72 locomotives have been preserved:

Number	Manufacturer	Equipment manufacturer	Date manufactured	Date retired	Location	Notes
ED72 1	Toshiba	Toshiba	11 August 1961	15 May 1976	Kyushu Railway History Museum, Kitakyushu, Kyushu, Japan	Displayed under shelter

Gallery