JNR Class ED70

JNR Class ED70
ED70 1 in August 2023
Technical specifications
Manufacturer(s)	Shin-Mitsubishi Jukōgyō
Constructed	1957, 1959
Number built	19
Classification	B-B
Dimensions	14,260 – 14,460 mm × 2,800 mm × 4,150 mm
Gauge	1,067 mm (3 ft 6 in)
Current collector	Pantograph
Electric system(s)	20 kV AC (60 Hz) 20 kV AC (50/60 Hz) (ED70 19)
Traction system	Continuous voltage control using a combination of low voltage tap changers and mercury rectifier tap changers
Service information
In service	1957 – 1975
Number in service	None
Fleet numbers	ED70 1 – ED70 19
Preservation information
Preserved	1
Number scrapped	18

The JNR Class ED70 is a Japanese AC electric locomotive operated by the Japanese National Railways from 1957 to 1975.

History

The ED70 was designed for the anticipation of the electrification of the Hokuriku Main Line; it was Japan's first AC electric locomotive that was produced in any significant volume. In contemporary marketing material the ED70 was advertised as "the world's first 60 cycle electric locomotive".

Eighteen locomotives were produced in 1957; Mitsubishi manufactured both the mechanical and electrical equipment of the locomotive under their Shin-Mitsubishi and Mitsubishi Denki arms. The locomotives were operated exclusively on the Hokuriku Main Line, pulling passengers and freight. ED70 19 was built in 1959, featuring different AC equipment allowing it to run on the Tōhoku Main Line with lower cycles (50 Hz as opposed to 60 Hz) as well as equipment to improve its adhesion coefficient. After the EF70 and ED74 locomotives were introduced, they were relegated to passenger and baggage trains.

The opening of the DC-only Kosei Line affected operations of AC locomotives, including those on the Hokuriku Main Line; spare parts for the ED70 were also hard to source as this locomotive was essentially a prototype for future AC locomotives. To combat these issues, the dual-voltage EF81 was introduced in large numbers, eventually becoming a mainstay of the JNR locomotive fleet. All locomotives were withdrawn by 1975.

ED70 1, located at the Nagahama Tetsudo Square in Nagahama, Shiga, is the only preserved ED70.

Design

The ED70s featured a semi-streamlined design with a headlight mounted on the roof.

Specifications

The ED70s used a Quill drive system. MT100 traction motors were used on the locomotives. The locomotive was based on the earlier ED45 prototype locomotives.

Preservation

The following Class ED70 locomotives have been preserved:

Number	Manufacturer	Equipment manufacturer	Date manufactured	Date retired	Location	Notes
ED70 1	Shin-Mitsubishi Jukōgyō	Mitsubishi Electric	15 July 1957	7 November 1972	Nagahama Tetsudo Square, Shiga, Japan	Displayed indoors; displayed next to D51 793