An electric–steam locomotive is a

steam locomotive A steam locomotive is a locomotive that provides the force to move itself and other vehicles by means of the expansion of steam. It is fuelled by burning combustible material (usually coal, Fuel oil, oil or, rarely, Wood fuel, wood) to heat ...

that uses electricity to heat the water in the

boiler A boiler is a closed vessel in which fluid (generally water) is heated. The fluid does not necessarily boil. The heated or vaporized fluid exits the boiler for use in various processes or heating applications, including water heating, centra ...

to create steam instead of burning fuel in a firebox. This is a highly unusual type of locomotive that only makes economic sense under specific conditions. Normally, it would be much more efficient to build and use an

electric locomotive An electric locomotive is a locomotive powered by electricity from overhead lines, a third rail or on-board energy storage such as a Battery (electricity), battery or a supercapacitor. Locomotives with on-board fuelled prime mover (locomotive), ...

. However, lack of time and resources (as during wartime), lack of

coal Coal is a combustible black or brownish-black sedimentary rock, formed as rock strata called coal seams. Coal is mostly carbon with variable amounts of other Chemical element, elements, chiefly hydrogen, sulfur, oxygen, and nitrogen. Coal i ...

or similar fuel, and the presence of relatively cheap and available electricity may make conversion of an existing steam locomotive into an electric–steam locomotive a viable proposition.

Switzerland

Switzerland has no natural reserves of coal, but the mountainous region offers plentiful, and cheap,

hydroelectricity Hydroelectricity, or hydroelectric power, is Electricity generation, electricity generated from hydropower (water power). Hydropower supplies 15% of the world's electricity, almost 4,210 TWh in 2023, which is more than all other Renewable energ ...

. By the outbreak of the

Second World War World War II or the Second World War (1 September 1939 – 2 September 1945) was a World war, global conflict between two coalitions: the Allies of World War II, Allies and the Axis powers. World War II by country, Nearly all of the wo ...

, of SBB lines (73.6% of the network) had been

electrified Electrification is the process of powering by electricity and, in many contexts, the introduction of such power by changing over from an earlier power source. In the context of history of technology and economic development, electrification refe ...

, whilst the price of imported German coal kept rising. In an attempt to save on coal the

Swiss Federal Railways Swiss Federal Railways (, SBB; , CFF; , FFS) is the national railway company of Switzerland. The company was founded in 1902 and is headquartered in Bern. It used to be a State-owned enterprise, government institution, but since 1999 it has be ...

fitted two small

0-6-0 is the Whyte notation designation for steam locomotives with a wheel arrangement of no leading wheels, six powered and coupled driving wheels on three axles, and no trailing wheels. Historically, this was the most common wheel arrangement used o ...

steam shunters of the class E 3/3 with a

pantograph A pantograph (, from their original use for copying writing) is a Linkage (mechanical), mechanical linkage connected in a manner based on parallelograms so that the movement of one pen, in tracing an image, produces identical movements in a se ...

. Power was taken from

overhead lines An overhead line or overhead wire is an electrical cable that is used to transmit electrical energy to electric locomotives, Electric multiple unit, electric multiple units, trolleybuses or trams. The generic term used by the International Union ...

(, Hz), and fed to heating elements, via two transformers rated together at . The modified E 3/3 8521 was brought into use on 13 January 1943; 8522 followed on 11 February 1943. They could run up to 20 minutes without power supply once the boiler had been charged to full pressure, similar to a

fireless locomotive A fireless locomotive is a type of locomotive which uses reciprocating engines powered from a reservoir of compressed air or steam, which is filled at intervals from an external source. They offer advantages over conventional steam locomotives of ...

. The firebox was retained, usually keeping hot

ember An ember, also called a hot coal, is a hot lump of smouldering solid fuel, typically glowing, composed of greatly heated wood, coal, or other carbon-based material. Embers (hot coals) can exist within, remain after, or sometimes precede, a ...

s, with a classic fire for longer operation on non-electrified tracks. The water circulation pump, the control circuit and the lighting were powered by a battery that was charged from a rectifier fed by one of the transformers. The system was capable of producing about of steam per hour at pressure. It weighed about , increasing the weight of the locomotive from to , and allowed a saving of of coal per working day. Bringing the locomotive to pressure took about one hour. The electric heaters were removed in 1951 from locomotive 8521 and in 1953 from 8522. As of 2013, locomotive E 3/3 8522 was still in (museum) service on the Sursee–Triengen railway as an ordinary steam engine with no electric heating.

Canada

A Canadian patent for an electric–steam locomotive was granted as recently as 1992. The drawing shows a Crampton type 8-4-0 but its intended use is unknown.

Electric pre-heater

A conventional coal-fired or oil-fired steam locomotive may be prepared for service by using an external electric pre-heater. This allows steam to be raised gradually during the night so that the locomotive will be ready for use in the morning. Modern steam locomotives, such as the rack locomotives of

Brienz–Rothorn railway The Brienz Rothorn Railway (, BRB) is a tourist rack railway in Switzerland, which climbs from Brienz, at the eastern end of Lake Brienz, to the summit of the Brienzer Rothorn. The railway is 7.6 kilometres (4.7 mi) long, is built to 800 ...

and DLM's modernised class 52.80 locomotive, are fitted with internal electric heaters.
advantages of modern steam as given on the pages of DLM AG, Switzerland. This allows keeping the well insulated boiler warm overnight or even to start heating automatically in the early morning.

Models

The electric–steam system is also used in some small-scale model steam locomotives. In September 2003

Hornby Railways Hornby Hobbies Limited is a British-owned scale model manufacturing company which has been focused on rail transport modelling, model railways. Its roots date back to 1901 in Liverpool, when founder Frank Hornby received a patent for his Meccan ...

released its first steam-powered 00 gauge locomotive, a scale model locomotive where the boiler is heated by electric power collected from the running rails. However mistakes in the instruction manual and video lead to operator error and thus poor publicity for the models. Furthermore, the need to boil the water means that these engines came with a dedicated power supply/controller to provide more voltage and current.

Literature

* Alfred Moser: ''Der Dampfbetrieb der schweizerischen Eisenbahnen 1847–1966''. 4. nachgeführte Auflage. Birkhäuser, Stuttgart 1967, S. 269. (detailed description in German)

References

Additional reading

* *

External links

Pictures on www.douglas-self.com

{{DEFAULTSORT:Electric–steam locomotive Steam locomotives Electric locomotives