Electro-diesel locomotive

British Rail Class 73, no. E6013 (73107) at Rowsley South, on the Peak Railway on 17 April 2003. This locomotive was on loan from Fragonset Railways, and has since returned to main-line service with RT Rail.

This is effectively an electric locomotive with a relatively small auxiliary diesel prime mover intended only for low-speed or short-distance operation (e.g. British Rail Class 73). Some of these, such as the British Rail Class 74, were converted from electric locomotives. The Southern Region of British Railways used these locomotives to cross non-electrified gaps and to haul boat trains that used tramways at the ports of Southampton and Weymouth. For economy, the diesel engine and its generator are considerably smaller than the electric capacity. The Southern types were of 1,600 hp or 'Type 3' rating as electrics, but only 600 hp as diesels.[1] Later classes had as much as 2,500 hp 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.

This is effectively a diesel locomotive with auxiliary electric motors (or connections to the existing traction motors), usually operating from 750 V DC third rail where non-electric traction is banned (e.g. EMD FL9, GE Genesis P32AC-DM, EMD DM30AC). The primary function for these models is to provide a "one-seat ride" (a rail trip that doesn't 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; such locomotives 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.

With modern electronics, it is much easier to construct (or adapt) an electro-diesel locomotive or multiple-unit which is equally at home running at high speeds both "under the wires" and under diesel power (e.g. British Rail Class 88, Bombardier ALP-45DP). These will 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.

• Gmeinder class 478.6[2] diesel and 750 V DC third-rail (bottom contact).
• Voith Futura, a 2009 CREAM Project[3] concept locomotive rebuilt from DB 240 002.[4]
• Bombardier TRAXX "Last Mile Diesel", mainly electric. Orders signed 2010, to be delivered probably 2012.[5]

Pesa Marathon at Inowrocław, working a goods train during tests by Lotos Kolej

• Pesa 111Ed Gama Marathon – mainly electric, with auxiliary diesel engine enabling last-mile operation on non-electrified tracks. Gama Marathon was first presented in 2012 at InnoTrans Berlin. The locomotive then underwent a series of tests with rail operators Lotos Kolej (in goods traffic) and PKP Intercity (in passenger traffic),[6][7] after successful conclusion it was offered on the market.[8] In July 2015 the Polish train-operating company Locomotiv bought the prototype and signed order for further two Marathons.[9]
• Newag Dragon – version of this electric freight locomotive for the Freightliner's Polish branch, Freightliner PL Sp. z o.o. (five units delivered in 2016) is equipped with auxiliary diesel engine.[10]
• Newag Griffin – a version of this electric freight locomotive, leased to Lotos Kolej in 2017 for 7 years with a provision to extend the lease, is equipped with auxiliary diesel engine.[11]

• FEVE 1.900 Series,[12] 1500 V DC overhead wires. This series is a rebuild of FEVE 1.000 Series locomotive.
• Euskotren TD2000 Series, 1500 V DC overhead wires. This is a new construction locomotive. Built by CFD-Bagnères and Ingeteam.
• CAF Bitrac 3600, 3000 V DC overhead wires. October 2007 order for nine freight Co-Co locomotives.[13] Available in Bo-Bo and Co-Co wheel configuration, 1,435 or 1,668 mm (56.5 or 65.7 in) gauge, and as freight or passenger versions of 120 and 180 km/h (75 and 112 mph) maximum speeds respectively.[14]
• Locomotives for RENFE Class 130, by Talgo.
• Locomotives for RENFE Class 730, by Talgo.

Light dual-mode (electric and diesel) shunter SBB Tem III 346 at work

• Rhaetian Railway Gem 4/4 801 and 802, 1000 V DC overhead wires (Bernina Railway)
• Swiss Federal Railways Tem I 251–275 (1950–57), Tem II 276–298 (1967) and Tem III 321–365 (1954–62) shunters (Tem III see image) of which only few are still in service.
• Swiss Federal Railways Eem 923 shunters using both 15 kV 16.7 Hz and 25 kV 50 Hz overhead wires and a 360 kW auxiliary diesel engine are on delivery from Stadler Rail's Winterthur plant.[15]

An experimental electro-diesel locomotive, DEL120, was built by London Underground in 1940 but was not a success. Two types have been built whose electricity source was a 750 V DC third rail.

• British Rail Class 73, dating from 1962 – the more successful design, with some still in regular use. They originally had lower power output in the diesel mode, but are re-engined to provide more power. (2020, 59 years since introduction)
• British Rail Class 74 – rebuilt from British Rail Class 71 electric locomotives in 1967 and withdrawn by 1977.

Electro-diesel locomotives whose electricity source is 25 kV 50 Hz AC overhead line include:

• British Rail Class 88 – locomotive used by Direct Rail Services. Introduced in 2017.

RZD OPE1 electro-diesel locomotive

In Russia, a number of electro-diesels were built which had both pantographs and diesel prime movers. These included:

ED18 (ЭД18) electro-diesel

• ED16 (ЭД16),[16] ED18 (ЭД18),[17] and TEU1 (ТЭУ1)[18] narrow gauge models
• OPE1 (ОПЭ1),[19] OPE2 (ОПЭ2),[20] NP1 (НП1),[21] PE2(M) (РЭ2(М)), and EL20[22] standard-gauge locomotives used mostly in quarries

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• Bombardier ALP-45DP – 20 locomotives ordered for the Mascouche line (AMT). It is a joint order with the New Jersey Transit order.[23] They provide a through journey on this mostly un-electrified new line, which joins an existing electrified commuter line to access Montreal's Central Station through the poorly ventilated, 25 kV AC electric only Mount Royal Tunnel.[23]

Metro-North's GE Genesis P32AC-DM at Ossining station

New Haven #140 "Roger Williams", unique Budd railcar-based train at Danbury Railway Museum, US-CT.

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:

• P32AC-DM – dual-mode version of GE Genesis, primarily diesel, electric mode is only used for service to Grand Central Terminal from Poughkeepsie or Wassaic, or Penn Station from Albany, Rutland, or Niagara Falls. They are also used on the Albany-New York section of trains between Penn Station and Chicago, Montreal, and Toronto. Those trains stop in Albany to switch to full diesel GE Geneses for the remainder of the journey.[24]
• EMD DM30AC – specific to Long Island Rail Road, primary diesel, electric mode is only used for service to Penn Station.
• Bombardier ALP-45DP[25] – 35 locomotives purchased by NJ Transit (with 17 more on order), to bridge gaps between non-electrified and electrified sections of track into New York Penn Station.[23][26] These trains have been used to provide a "one-seat ride" to New York Penn Station both for commuters using non-electrified portions of the system.[27]

The following were retired from New York City service:

• Baldwin RP-210 – primarily diesel-hydraulic, third-rail electric mode for short-term use only. All scrapped.
• "Roger Williams" - streamlined 6-car lightweight DMU passenger train, built by Budd Company in 1956 for New York, New Haven and Hartford Railroad; primarily diesel-hydraulic, third-rail electric mode for short-term use only. Three cars preserved.
• Fairbanks Morse P-12-42 – primarily diesel-electric, third-rail electric mode for short-term use only. All scrapped.
• EMD FL9 – primarily diesel-electric, third-rail electric mode for short-term use only. Several examples preserved and/or in service on heritage railroads.
• GE three-power boxcab - tri-mode switcher locomotive model built in 1930, was also capable of operating as a battery locomotive. All retired and scrapped.
• GE/Garrett gas turbine MUs - primarily electric, but built with gas turbines to allow operation outside of third rail electrification. All scrapped.

Spoornet Class 38-000 38-008 in electric mode at Sentrarand, Gauteng, ZA

• The South African Class 38-000 is a 3 kV DC electro-diesel locomotive designed by Consortium under the leadership of Siemens and built by Union Carriage and Wagon (UCW) in Nigel, Gauteng, South Africa. Between November 1992 and 1993 fifty of these locomotives were placed in service by Spoornet, formerly the South African Railways (SAR) and later renamed Transnet Freight Rail (TFR). The diesel engine enables the locomotive to shunt on unelectrified sidings.[28]

• Stadler Euro Dual, proposed 25 kV 50 Hz AC overhead wires (Tanzania Standard Gauge Railway)

A WDAP-5 await testing at Banaras Locomotive Works, Varanasi.

• The Indian locomotive class WDAP-5 is a class of Electro-diesel locomotive that was developed in 2019 by Banaras Locomotive Works (DLW), Varanasi for Indian Railways. The model name stands for broad gauge (W), Diesel (D), AC Current (A), Passenger (P) and 5000 Horsepower(5). The locomotive can deliver 5000HP in electric mode and 4500HP in diesel mode. Since 2016, Indian Railways has pushed for greater electrification of the railway network.[29] In this interest, the government, in 2019, approved plans for 100% electrification.[30] So far Indian Railways has electrified 39,866 RKMs which accounts for about 63% of the total route kilometres.[31] Using electric locomotives allows the railways to save time by giving a faster acceleration and also saves fuel costs. However, these advantages are offset under certain circumstances where the route of the train is partly electrified. In such cases, trains used to run with a diesel locomotive in non-electrified sections and would be switched with an electric locomotive as soon as they enter an electrified section. Instead of the benefits of electrification, Railways observed a loss of punctuality in such trains due to valuable time being lost to switch between diesel and electric locomotives. To counter this, in August 2019, Railways issued a circular, asking all zones to haul trains with a diesel locomotive if their route was not completely electrified.[32] This meant that electrification of railway lines, unless completed end-to-end, did not provide any advantage. This problem had been identified by the Railways, way back in 2016, which is when RDSO was requested to study the feasibility of dual-mode locomotives as a stop-gap until 100% electrification was achieved.[33]