Several non-electrified commuter routes lie between New York City and several cities in New Jersey. However, since the crossing under the Hudson River can only be used by electric locomotives, passengers used to have to switch from diesel-powered trains to other trains. In order to ensure an uninterrupted journey, New Jersey Transit initially ordered 26 passenger locomotives with fully-fledged diesel and electric drives from Bombardier in Kassel in 2008, with options for a further 63. Because Canadian operator Exo, which operates commuter rail services around Montreal, had the same problem with the Mount Royal Tunnel, they joined NJ Transit and ordered 20 with an option for 10 more.

Bombardier based the ALP-45DP on the ALP-46, which was an all-electric locomotive and is closely related to the European TRAXX locomotives. The designation stands for “American Locomotive Passenger”, 4 axles, 5 megawatts, “Dual Power”. All the equipment had to be accommodated in a four-axle locomotive with a maximum axle load of 72,000 pounds anyway. Since the locomotives were only to be used in push-pull trains with control cars, a second driver's cab was not required.

Like the ALP-46, the drive technology for electric operation is based on that of the TRAXX 2E, which is used in Germany as class 186 and enables a top speed of 125 mph or 201 km/h. In the ALP-45DP, however, it only delivers 5 megawatts. In order to achieve an output of more than 3,000 kW in diesel operation, the choice fell on two light, fast-running twelve-cylinder engines from Caterpillar, each with its own generator. These are designed in such a way that if one motor fails, the locomotive can still be used with the other. The top speed is limited to 100 mph or 161 km/h in diesel mode.

The drive technology is designed in such a way that the change between the modes can even take place while driving and there is no interruption to the power supply of the train. However, the NJ Transit locomotives were manipulated in such a way that the change can only take place when stopping at a station in order to prevent them from gliding along without power during the 100 seconds required for this. Regardless of the current operating mode, up to 1,000 kW can be diverted to supply the passenger cars, which reduces the drive power available at the wheel to 2,039 kW in diesel mode.

At NJ Transit, the first delivery replaced the various passenger variants of the EMD GP40. After the first batch, 17 more were ordered in 2017. In 2020, another eight were ordered to replace Alstom's older PL42AC. At Exo, in 2019, the part of the route they traveled in electric mode was integrated into the new driverless metro. They are now only operated in diesel mode.

For traffic on routes that are not fully electrified, DRS ordered ten dual-powered locomotives from Vossloh España (today Stadler). Under the overhead line, they deliver 4,000 kW and the diesel engine delivers 710 kW, which is more than conventional electric locomotives with last-mile function. They are based on the UKLight, which is in service as class 68 and have 70 percent common parts with it. At first glance, they can only be distinguished visually by the additional pantograph. The engine here is a smaller Caterpillar C27 with only 27 liters displacement from twelve cylinders. DRS remained the only customer of the Class 88. The locomotives are mainly used to pull freight trains, but often also to pull passenger trains.

With progressing development, it was possible to modify the Vectron DE into a dual-power locomotive. By reducing the diesel tank from 2,600 to 1,500 liters, a transformer could be accommodated under the locomotive's frame. Together with the pantograph and other electrical equipment on the roof, it is now possible to feed the traction converters from either the overhead line or the diesel generator.

The original Vectron Dual Mode is used as class 248 and has the same engine as the Vectron DE, which has since been discontinued. This means a gross engine power of 2,400 kW and a traction power of 2,000 kW. In electric mode, 2,400 kW are available for traction. The largest operators include the Paribus Group, DB Fernverkehr, ITL and Rheincargo, other locomotives are used in numbers of mostly just one or two locomotives by a whole range of smaller customers.

DB Cargo 249 003 with visible shunter platform at Innotrans Berlin 2022

Nelso Silva

Since the DM with an axle load of 22.5 tonnes cannot be used on some sidings, the DM Light has been delivered in parallel since 2022 as class 249. In electric mode, the power fell only slightly to 2,210 kW and a Cummins QST 30-L delivers 950 kW, of which 750 kW arrive at the wheel. The result is an axle load of only 21 tonnes. With the DM Light, DB Cargo is replacing part of the former V 90 in shunting operations. Due to the lack of side windows, this got additional microphones and cameras and also shunting platforms, which increase the overall length. After the first series of 100 pieces for DB Cargo, there are still options for more than 200 pieces.

With older electro-diesel locomotives, compromises had to be made between the two types of power, since it was not possible to accommodate two full-fledged power systems. As development progressed, Stadler succeeded in combining an electric locomotive with an output of 7,000 kW and a diesel locomotive with 2,800 kW in one locomotive body. The development was primarily driven by the Havelland Railway, which needed a locomotive for the Rübelandbahn that could also work under 25,000 volts and also provide full traction on the non-electrified connecting lines.

The basis was the Euro4000, which Vossloh manufactured in Valencia, Spain. After the plant was bought by Stadler in 2015, this locomotive could be used as a basis and further developed into a modern two-power locomotive. The EMD engine was replaced with the more compact Caterpillar C175-16 that Vossloh had already used in the British class 68. In electrical operation, the locomotive can be used with four systems with direct and alternating current. Under 25,000 volts it has an output of 7,000 kW and under 15,000 volts only 6,150 kW. Since there is not such a high level of power available in DC operation, the diesel engine can additionally be used here. The power mode can also be switched while running, but this is not permitted in Germany.

At the same time as the EuroDual, the Euro4001 was developed as a pure diesel locomotive with the same engine. A purely electric locomotive with a maximum of 6,200 kW under 25,000 volts is offered as the Euro6000. The most powerful variant is the Euro9000, which has an output of 9,000 kW when operated with alternating current. The diesel engine is declared here as a last-mile diesel and has an output of only 900 kW. Optionally, however, even two of these engines can be installed.

The EuroDual and the Euro9000 are mainly operated by German railway companies and leasing companies. Seven are used in Turkey and 30 more will be delivered to GB Railfreight in the UK from 2025. Although they are also optionally available for 160 km/h, they are normally only used in front of freight trains. The Euro6000 has so far only been delivered to customers from the Iberian Peninsula, most of them in Iberian broad gauge and some in standard gauge.