JNR Class ED75

The design descended from the silicon-rectifier ED74 and adopted low-voltage tap-changing controlled by magnetic amplifiers to secure adhesion, with provision for later conversion to thyristor control. Because the locomotive was distinguished from other control types by this magnetic-amplifier system, the base sub-classes became known as the "M" type. To work the Tohoku Main Line, where 1,200-tonne loads had to be hauled over gradients exceeding 20‰ scattered along the route, the type was designed for double-heading under multiple-unit control and fitted with a front gangway door. Its external livery was the standard AC-locomotive colour, Red No. 2.

Two prototypes, ED75 1 and 2, were delivered in 1963, after which a further 158 locomotives were built from 1964; numbers 50 to 100 were equipped for cold regions and fitted with icicle cutters above the cab windows. Several sub-classes followed. Eleven ED75-300 machines (301–311) were built from 1965 to 1968 for Kyushu, the only members of the class built for a 60 Hz supply.

A single experimental ED75-500 (501) was built in 1966 by Mitsubishi Heavy Industries for the newly electrified Hakodate Main Line in Hokkaido; it used all-thyristor phase control in place of the M type's low-voltage tap-changing, and for this feature it was known as the "S" type although it was the only one built. Its specialised cold-region equipment made it 300 mm longer than the rest of the class, at 14,600 mm. No more were built: its thyristor control produced harmonics that caused severe inductive interference with signalling and communications, and it had no steam generator for the train heating the route required, so Class ED76-500, fitted with a steam generator, was built for the line instead.

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Ninety-one ED75-700 locomotives (701–791) were built from 1971 to 1976 for the Ou Main Line and Uetsu Main Line, distinguished by PS103 cross-arm pantographs and by measures against snow and salt corrosion; because unit 736 was written off in 1974 after a derailment caused by a landslide on the Uetsu Main Line, the ninety-one were never all in service at the same time. Thirty-four of them were rebuilt into Class ED79 locomotives for services through the undersea Seikan Tunnel. The ED75-1000 sub-class, introduced for the full electrification of the Tohoku Main Line and built from 1968 to 1976 for high-speed freight and 20-series sleeper trains, totalled 39 machines (1001–1039) and was nicknamed the "P" type; JR Freight began a life-extension refurbishment programme from 1993.

The class worked everything from limited express trains to ordinary freight, but from the 1980s its duties declined as Class EF81 locomotives took on more work, overnight passenger trains and freight services were cut, and local passenger trains were converted to electric multiple units. From the 17 March 2012 timetable revision the remaining scheduled JR Freight workings were completely replaced by Class EH500 locomotives, and all of JR Freight's ED75s were withdrawn by June 2012. As of 1 April 2016, just five locomotives — all ED75-700 machines operated by JR East, with three based at Sendai and two at Akita — remained in service. Ageing and the arrival of new types such as the GV-E197 series then thinned out JR East's remaining ED75-700s; the last two, 758 and 759, were hauled away for withdrawal in September 2025, and the class became extinct when 759 was struck off the register on 13 September 2025. Two examples are preserved: ED75 501 at the Otaru City Museum in Otaru, Hokkaido, and ED75 775 at The Railway Museum in Saitama. ED75 1, formerly preserved at Sendai Shinkansen Depot in Rifu, Miyagi, was scrapped in December 2019, and ED75 39 was scrapped in 1998. The ED75 design was also exported: it formed the basis of China Railways' Type 6K (derived from the EF66 and the ED75) and of the Congo/Zaïre Railways Class 2500.

• 1963Two prototypes, ED75 1 and ED75 2, are delivered, built by Hitachi and Mitsubishi, as the AC successor to Class ED71 for the newly AC-electrified Joban Line.
• 1971Production of the salt- and snow-resistant ED75-700 sub-class begins for the Ou Main Line and Uetsu Main Line; 91 locomotives (701-791) are built through 1976.
• 1986/198834 ED75-700 locomotives are rebuilt into Class ED79 locomotives for services through the undersea Seikan Tunnel between Honshu and Hokkaido. The year is given as 1986 or 1988.
• 2012From the 17 March timetable revision the remaining scheduled JR Freight ED75 workings are completely replaced by Class EH500 locomotives; JR Freight's last ED75s are withdrawn by June.
• 2025The last surviving units, ED75-700 machines 758 and 759 operated by JR East, are hauled away for withdrawal; ED75 759 is struck off the register on 13 September, marking the extinction of the class.