![OPE1A [ru; uk] industrial electro-diesel locomotive for quarry railways with primary electric locomotive and two diesel B-units OPE1A-044.jpg](http://upload.wikimedia.org/wikipedia/commons/thumb/d/d3/%D0%9E%D0%9F%D0%AD1%D0%90-044.jpg/250px-%D0%9E%D0%9F%D0%AD1%D0%90-044.jpg)
An electro-diesel locomotive (also referred to as a dual-mode or bi-mode locomotive) is a type of locomotive that can be powered either from an electricity supply (like an electric locomotive) or by using the onboard diesel engine (like a diesel-electric locomotive). For the most part, these locomotives are built to serve regional, niche markets with a very specific purpose.
Electro-diesel locomotives are used to provide continuous journeys along routes that are only partly electrified without a change of locomotive, avoid extensive running of diesel under overhead electrical wires and giving a solution where diesel engines are banned. They may be designed or adapted mainly for electric use, mainly for diesel use or to work well as either electric or diesel. [1]
In most cases, electro-diesel locomotives use diesel–electric transmission and the same traction electric motors when moving in both autonomous and electric mode, although with different power. However, locomotives with diesel-mechanical or diesel-hydraulic transmission and separate electric motors were also created.
Note that, as well as the electric multiple unit (EMU) and diesel multiple unit (DMU), where no discrete locomotive is present, an electro-diesel (bi-mode) multiple unit train is called electro-diesel multiple unit (EDMU) or bi-mode multiple unit (BMU). [1]
This is effectively an electric locomotive with a relatively small auxiliary diesel prime mover intended only for low-speed or short-distance operation. For economy, the diesel engine and its generator are considerably smaller than the electric capacity, which occupies most of the interior space of a locomotive. Unlike typical diesel locomotives, where the diesel engine is located in the center of the frame, in mainly electric dual-mode locomotives the auxiliary diesel engine and generator can be located at the side of the engine room. [1]
The output power of a diesel-generator in mainline locomotives of this type is similar to the power of engines of small shunting locomotives (usually no more than 800 kW) and is significantly smaller than the nominal power of electric motors when they are powered from the electric supply. For example, The Southern Railway types were of 1,600 horsepower (1,200 kW) or 'Type 3' rating as electrics, but only 600 horsepower (450 kW) as diesels. Later classes had as much as 2,500 horsepower (1,900 kW) on electric power, but still the same diesel engines. Despite this large difference, their comparable tractive efforts were much closer (around three-quarters as diesels) and so they could start and work equally heavy trains as diesels, but not to the same speeds. [2]
These locomotives are usually operated on electrified railway lines that have non-electrified sections in the short final part of the route, the so-called "last mile". That can be a small branch lines, stations with non-electrified siding tracks or tracks with another type of electrification, lines at cargo terminals, industrial facilities, construction sites, wharves, factories, mines, quarries at loading points where overhead lines cannot be used due to the need to load cargo. That eliminates the need to change a mainline locomotive to a shunter locomotive. [3] Also in case of a third rail electrification, these locomotives can be used to cross non-electrified gaps (e.g. level crossings) or tracks with unpowered third rail (e.g. at freight yards during shunting operations or on metro lines at night, where the power supply is temporarily switched off for the safety of the working personnel).
The Southern Region of British Railways used mainly-electric dual-mode locomotives from 1960-s to cross non-electrified gaps and to haul boat trains that used tramways at the ports of Southampton and Weymouth, and also at freight yards. Some of these locomotives were originally built as electro-diesel locomotives at the factory (e.g. British Rail Class 73), others were converted from electric locomotives (such as the British Rail Class 74). [2]
Since the 2010s, in continental Europe, several locomotive manufacturers have started to produce electric locomotives with an optional small "last mile diesel", and this name was getting popular. [3] These are electric locomotives with a small diesel engine of truck type (usually with 180–300 kW (240–400 hp) power output), used in low speed, low gear, for operation at small flat freight yards or with short freight trains at branch lines, eliminating the need for a shunter locomotive. [4]
At the same time, locomotives with more powerful diesel engines, which are also capable of self-powered operations when hauling a normal freight train at low speeds, were also produced (e.g., British Rail Class 88 with 710 kW (950 hp) diesel engine). In terms of power, locomotives of this class takes an intermediate position between primarily electric locomotives with auxiliary diesel engines and fully dual-mode locomotives, [5] though they are mostly limited to last mile operations. [6]
This is effectively a diesel locomotive with auxiliary electric capacity for power supply from electric network (or auxiliary electric motors in case of diesel-hydraulic transmission), usually operating from a low-voltage catenary (e.g. 750 V DC third rail in the USA or 1000 V DC overhead lines in Switzerland), where non-electric traction is banned. These locomotives are generally based on conventional diesel-electric locomotives and can be converted relatively easily by adding current collectors (pantographs or contact shoes), contactors and voltage regulation equipment when powered from an electric supply. Due to the low input voltage and current limitations in electric mode, the power output on the traction motors and the maximum speed of such a locomotive are lower than when powered by a diesel engine.
The primary function for these models is to provide a "one-seat ride" (a rail trip that does not require a transfer to a different train) between the electrified and non-electrified sections of a rail system or to allow trains to run through tunnels or other segments of track where diesel locomotives are generally prohibited due to their production of exhaust. [1]
In the United States, such locomotives (e.g. EMD FL9, GE Genesis P32AC-DM, EMD DM30AC, SC-42DM) are used for certain trains servicing the New York City terminals of Grand Central Terminal and Penn Station, as the various rail tunnels into Manhattan have exhaust restrictions. Once out of the tunnels, the engines are started and operation is as a normal diesel locomotive. [1]
This type of dual-mode locomotives has a high power and traction force at home running at high speeds both "under the wires" and under diesel power. These locomotives normally operate under pure electric traction where possible, and use the diesel engines to extend the journeys along non-electrified sections which would not be cost effective to electrify. They may also be used on long cross-country routes to take advantage of shorter sections of electrified main lines. [1]
Historically, most mainline dual-mode locomotives have had mainly electric or mainly diesel designs, as it was difficult to fit a powerful diesel engine and powerful electric capacity into a single unit while maintaining the permissible axle load. [1] Mostly, full-fledged dual-mode electric-diesel locomotives were either small shunting and narrow-gauge locomotives with a low-powered diesel engine, which had a comparable power outputs in electric and diesel modes, [7] or two-unit industrial freight locomotives with separate electric and diesel sections, united by a common control system and power supply for traction electric motors (for example, Soviet quarry electric diesel locomotives OPE1 with two A-units [8] or electric diesel locomotives OPE1A/OPE1B with the main electric A-unit and diesel B-unit [9] ).
Since the 2010s, thanks to the development of technologies and the emergence of sufficiently powerful and compact high-speed turbocharged diesel engines, as well as compact power electronics, it has become possible to create single full-fledged dual-mode and even tri-mode (with battery-electro-diesel) locomotives with an acceptable axle load (e.g. Stadler Euro Dual, Bombardier ALP-45DP). With modern electronics, it is much easier to construct (or adapt) such locomotives. [10] [11]
The electrical equipment and the diesel generator usually occupy more or less equal space in the engine room, depending on the power and size of the diesel. Although the power output of the diesel generator and traction electric motors of such locomotives is usually significantly lower than when powered from overhead lines in pure electric mode (especially on lines with high-voltage AC electrification, and can be several times less), it is still sufficient to maintain normal speed with a train. For example, in Stadler Euro Dual locomotives, the diesel engine power can vary from 1–2.8 MW (1,300–3,800 hp) in diesel mode and up to 7 MW (9,400 hp) in electric mode. [12]
A specialized type of electro-diesel locomotive is the hybrid locomotive. Here, the electricity comes from a battery charged by the diesel engine rather than from an external supply. An example is the Green Goat switcher GG20B by Railpower Technologies, a subsidiary of R.J. Corman Railroad Group since 2009. [13] [1]
In Russia, a number of electro-diesels were built which had both pantographs and diesel prime movers. These included:
Narrow-gauge dual-mode locomotives:
Industrial freight locomotives:
Mainline freight locomotives:
Electro-diesel subway locomotives for London Underground include:
Electro-diesel locomotives whose electricity source is 650 — 750V DC third rail include:
Electro-diesel locomotives whose electricity source is 25 kV 50 Hz AC overhead line include:
Several, primarily diesel locomotive types and a multiple-unit have been built to operate off a 750 V DC third rail into the New York City terminals of Grand Central Terminal and Penn Station (with the third rail system being rarely used on open-air tracks).
The following are in service:
The following were retired from New York City service:
Two electro-diesel locomotive models has been manufactured: FXSY and FXSY3.
As an alternative to electro-diesel locomotives, some railways used mixed consists of electric and diesel locomotives, or a locomotive and a trailer power car of a different type, coupled and connected with a multiple unit train control system. Typically such multiple working is not supported by the locomotive control system, which allows to operate only locomotives of a similar type (either electric or diesel), since a typical electric and diesel-electric locomotive does not have the necessary buttons and monitoring devices on its control panels to operate power equipment of a paired locomotive with another power type, and a multiple unit electric code protocol does not support all necessary signals. However, locomotives can be modified and equipped with additional controls in driver's cab and remote control equipment to allow dual-mode operation with a locomotive or power trailer with another power source.
In rare cases, an electric and a diesel-electric locomotive can be modified with additional remote control equipment and coupled in mixed dual-mode pairs with the ability to control power source and traction equipment of a paired locomotive. Unlike full-fledged two-unit electro-diesel locomotives (for example, OPE1 or OPE1A), where the electric circuits of the traction motors of both electric and diesel sections are united into a common network regardless of the energy source used, in locomotives in a married pair they are completely independent, and only the control system can be combined.
In South Africa on the Sishen–Saldanha Orex line, Class 9E and Class 15E electric locomotives run in mixed consists with GE Class 34 series (Classes 34-000, 34-400, 34-500 and 34-900) and Class 43-000 diesel-electric locomotives to haul the 342-wagon and almost 4-km long iron ore trains. Although this line is completely electrified with high voltage 50 kV AC overhead lines, electrical sub-stations are located very sparsely with large gaps between each other, which can cause huge voltage drops, so their power is insufficient to supply only electric locomotives in sufficient quantity to pull such a long and heavy trains, but the partial usage of diesel locomotives allows to solve this problem [49] [50] Each Class 9E or Class 15E electric locomotive is equipped with controls for diesel locomotive power equipment and serves as the master of each mixed consist, controlling its respective diesel-electric companions by means of a Slimkabel (smart cable). Each locomotive set usually consists of two or three locomotives, including one or two Class 9E or 15E electric and one or two Class 34 or 43-000 diesel-electric locomotives. In effect, each ore train is therefore made up of three separate 114-wagon trains consisted together, with the locomotives of all three trains and the pusher locomotive at the rear end all controlled by means of a Locotrol radio distributed power control system by one crew in the leading electric locomotive. [49] [50] [51]
In Uzbekistan in 2000, as an experiment to reduce the travel time of passenger trains, a single unit of a two-unit VL80S electric locomotive and a single unit of a two-unit 2TE10M diesel-electric locomotive were coupled in a semi-permanent consist, which was designated as a pseudo-electro-diesel locomotive ETT-0001. Initially these locomotives had completely different analog controls and electrical circuits, incompatible with each other, so control panels and electrical cables were taken from withdrawn locomotives of the same classes and duplicated in driver's cabins of each other locomotives on secondman's left part of the cabin. This coupling worked for several years on the Tashkent — Samarkand route with passenger trains: the train was pulled by the VL80S electric locomotive from Tashkent to Jizzakh, and by the 2TE10M diesel-electric locomotive from Jizzakh to Samarkand. After 2003, the electrification of the route to Samarkand was completed, and the coupling was disbanded, since it was no longer needed. [52]
In the United Kingdom, after the electrification of the East Coast Main Line in 1987, British Rail has decided to test new Class 91 locomotives in passenger service with loco-hauled Mark 3 carriages and Class 43 diesel-electric locomotives (power cars) taken from Intercity 125 (HST) diesel trainsets as surrogate driving van trailers, thus forming a push-pull dual-mode trainsets, because the new Mark 4 carriages with driving van trailers for these locomotives were not going to be finished in time. In order to provide a compatibility with Class 91 locomotives and buffered loco-hauled coaches, eight Class 43 power cars were modified through the removing of their lower valancing in favour of buffers and installing an additional time-division multiplexing remote control equipment which was also added to the Class 91 locomotives, so each locomotive could be controlled by its mate. At first, only electric locomotives were used for traction, while the diesel engines of the Class 43's were used only to supply head-end power to the passenger carriages. However, a long-term idling of diesel engines caused them to catch oil fire, and to prevent this, the Class 43's were also started to be used for traction in addition to the electric locomotive, working in mixed power mode and giving the Class 91's an extra boost when departing stations. These sets worked on the line between 1987 and 1991, when the first Mark 4 carriages including DVTs became available and entered service. After this, the Class 43 power cars were returned to regular operations with HST sets, and their remote control systems for electric locomotives were removed [53] .
In China, two CR200JS-G electro-diesel push-pull trainsets were built in 2021 for plateau operation, as part of CR200J Fuxing electric train family. Each train consists of HXD1D-J electric locomotive (power car) with 7200 kW power output on wheels at one end, FXN3-J two-unit diesel locomotive (two power cars) with 2×2700 kW power output on wheels (or 2×3500 kW on engines) at another end, and nine 25-T passenger coaches sandwiched between them. Electric and diesel power cars have their own independent traction motor circuits, but can be operated from cabs of each other via a digital train communication network. HXD1D-J is a special version of a conventional HXD1D electric locomotive manufactured by CRRC Zhuzhou Locomotive, and FXN3-J is a special version of a FXN3 two-unit diesel-electric locomotive manufactured by CRRC Dalian – both of them have modified body design with only one driver's cab and new aerodynamic shape and are adapted for joint operation as part of a train. [54] [55] These trains are served on Sichuan–Tibet railway. [56]
Some locomotives can be coupled with a powerful enough trailer head-end power car (diesel-generator car for electric or pantograph and transformer car for diesel-electric locomotive). A single-mode locomotive, as in the other case, is equipped with additional control panels for remotely operating this trailer and power cables for receiving power from it, which allows it to be used as a dual-mode locomotive.
In Russia, the Magnitogorsk Iron and Steel Works purchased eight EU-500 diesel generator cars with a 500 kW diesel-generator for joint operation with NPM2 industrial shunting electric locomotives, equipped with the option of remote diesel generator control for operation on non-electrified sections. These cars can also be used together with any other 1.5 kV DC electric locomotives (for example, LEW EL2) after they undergo modernization. [57]
A similar concept has found application in push-pull trains: