The BTB E2E, also known as F 2/2 and De 2/2, were a pair of Swiss electric locomotives operated by Burgdorf Thun Bahn (BTB) in the early twentieth century. They are the oldest

three phase Three-phase electric power (abbreviated 3φ) is a common type of alternating current used in electricity generation, transmission, and distribution. It is a type of polyphase system employing three wires (or four including an optional neutral r ...

locomotives designed for full service operation that have been preserved. The locomotives were built by

Brown, Boveri & Cie Brown, Boveri & Cie. (Brown, Boveri & Company; BBC) was a Swiss group of electrical engineering companies. It was founded in Zürich, in 1891 by Charles Eugene Lancelot Brown and Walter Boveri who worked at the Maschinenfabrik Oerlikon. In 1 ...

(BBC) and Schweizerische Lokomotiv- und Maschinenfabrik (SLM) and entered service in 1899. They were powered by two 750V AC

electric motor An electric motor is an Electric machine, electrical machine that converts electrical energy into mechanical energy. Most electric motors operate through the interaction between the motor's magnetic field and electric current in a Electromagneti ...

s which drove two axles. A two speed

gearbox Propulsion transmission is the mode of transmitting and controlling propulsion power of a machine. The term ''transmission'' properly refers to the whole drivetrain, including clutch, gearbox, prop shaft (for rear-wheel drive vehicles), differe ...

enabled the locomotives to travel at and , the latter for passenger transport. The gearbox was later upgraded, raising the speed to . Relegated to secondary duties when more powerful designs were introduced, the locomotives provided valuable service until 1930.

Description

Constructed in Switzerland by a collaboration between

(BBC), who provided the mechanics, and Schweizerische Lokomotiv- und Maschinenfabrik (SLM), who contributed the electrics, the two E2E locomotives were introduced to pull goods on the BTB. They were equipped with two 19-pole

s with a one hour rating of which powered a common shaft mounted on an auxiliary frame. Power was transmitted via a

countershaft A jackshaft, also called a ''countershaft'', is a common mechanical design component used to transfer or synchronize rotational force in a machine. A jackshaft is often just a short stub with supporting bearings on the ends and two pulleys, gear ...

and

coupling rod A coupling rod or side rod connects the driving wheels of a locomotive. Steam locomotives in particular usually have them, but some diesel and electric locomotives, especially older ones and shunters, also have them. The coupling rods transfer t ...

s to two axles to power four

driving wheel On a steam locomotive, a driving wheel is a powered wheel which is driven by the locomotive's pistons (or turbine, in the case of a steam turbine locomotive). On a conventional, non-articulated locomotive, the driving wheels are all coupled ...

s. The railway operated at 750V

AC, which was transmitted to the locomotive via a roof-mounted

pantograph A pantograph (, from their original use for copying writing) is a 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 second pen. If a line dr ...

and overhead wires. The locomotives were equipped with a 100 V circuit for lighting, heating and other auxiliaries. The E2E had a

wheelbase In both road and rail vehicles, the wheelbase is the horizontal distance between the centers of the front and rear wheels. For road vehicles with more than two axles (e.g. some trucks), the wheelbase is the distance between the steering (front ...

of and a total length of . Weight in service was . A driving cab with simple controls, including air brakes, was fitted to one end of the superstructure. A two speed

, switchable when the locomotive was stationary, was fitted. The lower gear allowed a maximum speed of on a slope of 25 ‰ drawing a load of . The higher gear was designed for the locomotive to travel at up to . The gearbox proved to be problematic and was revised by SLM in 1900. Later, the gearing was changed to allow for a higher speed of .

Service

The locomotives started operating on the railway between 1899, initially designated E2E. At first, they were used mainly for freight services, but the higher gear speed also allowed the locomotives to be used for passenger operations. With the introduction of more powerful locomotives, they were relegated to secondary duties. In 1902, they were redesignated F 2/2; subsequently they were reclassified as De 2/2 in 1922. Despite their obsolescence and the limitation of the two fixed speeds, the simple engine design proved reliable and the locomotives provided good service. After just over thirty years in service, they were retired in 1930.

Preservation

Both locomotives have been preserved as the first three-phase locomotives in full-service operation. No. 1 is part of the collection of the

Deutsches Museum The Deutsches Museum (''German Museum'', officially (English: ''German Museum of Masterpieces of Science and Technology'')) in Munich, Germany, is the world's largest museum of science and technology, with about 28,000 exhibited objects from ...

Freilassing Locomotive World The Freilassing Locomotive World (''Lokwelt Freilassing'') is a railway museum in the Berchtesgadener Land, which is operated with the cooperation of the town of Freilassing and the Deutsches Museum. The museum is located on the site of the former F ...

. No. 2 is housed at the

Swiss Museum of Transport The Swiss Museum of Transport or Verkehrshaus der Schweiz (literally "Transportation House of Switzerland") in Lucerne opened in July 1959 and exhibits all forms of transport including trains, automobiles, ships and aircraft as well as communicati ...

Lucerne Lucerne ( , ; High Alemannic German, High Alemannic: ''Lozärn'') or Luzern ()Other languages: gsw, Lozärn, label=Lucerne German; it, Lucerna ; rm, Lucerna . is a city in central Switzerland, in the Languages of Switzerland, German-speaking po ...

References

Citations

Bibliography

* * * {{DEFAULTSORT:BTB E2E Electric locomotives of Switzerland Preserved electric locomotives Standard gauge locomotives of Switzerland Railway locomotives introduced in 1899