An electro-diesel locomotive is a unit that can operate from either an external electric power source, or standalone with an onboard diesel engine, and on the railways of the former USSR is an interesting example – the ОПЭ1 and subsequent developments.
Developed in the 1960s to work on the open cut mine railways of the USSR, electrified with 10 kV AC 50 Hz overhead lines, a ОПЭ1 locomotive can be made up of a mix of four different kinds of unit:
- electric section (E) featuring a traction transformer, rectifier, pantograph, and driver’s cab.
- autonomous power supply section (T) featuring a diesel-generator set from a M62 diesel locomotive, and driver’s cab.
- motor section (M) featuring traction motors on locomotive bogies beneath a side dump freight wagon.
- motor booster section (M) featuring traction motors beneath a shortened locomotive body.
Which can then be arranged in a variety of ways:
- Three sections (electric locomotive, diesel locomotive and motor section) – the primary combination of traction units, able to work under overhead wires or autonomously (traction and braking in both modes are created by all 12 traction motors);
- Two sections (an electric locomotive and diesel locomotive, without motor section) – able to work under overhead wires or autonomously (power from both modes with rheostatic braking by 8 traction motors);
- One electric locomotive section (electric locomotive, without motor section or diesel locomotive) – work with the train in electric mode (4 traction motors);
- One diesel section (diesel locomotive, without a motor section or electric locomotive) – powered by a diesel generator (4 traction motors, but no resistive braking provided).
Following the collapse of the USSR production of the ОПЭ1 locomotive slowed, with a total of 417 electric/diesel locomotive combinations, 52 motor dump cars, and 32 traction power boosters manufactured by the time production ended in 2002.
The design was further refined as the ОПЭ1А introduced in the 1970s, which saw the locomotive body shrunk, improving the visibility for the train driver in the reverse direction.
More photos and video
ОПЭ1 locomotive shunts a rake of side dump wagons.
- Locomotive ОПЭ1-298, a combination of electric, diesel and motor booster units.
- Locomotive ОПЭ1-343, made up of one electric unit and two side dump wagons.
- ОПЭ1 locomotives at work at the Kemerovocoal mine in southwest Siberia
And related locomotives
The ОПЭ1 design concept was also applied to the ОПЭ2 electric locomotives developed in the 1970s – each features a ‘control’ electric locomotive coupled to two ‘motor dump cars’ to provide extra tractive power.
While American railroads call such locomotives slugs:
A railroad slug is an accessory to a diesel-electric locomotive. It has trucks with traction motors but, unlike a B unit, it cannot generate power on its own since it lacks a prime mover. Instead, the slug is connected to a powered locomotive, called the mother, which provides the needed electrical power to operate the traction motors, and the motor controls.
Which look much the same as the USSR examples already seen.