The Buchli drive is a transmission system used in

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), ...

s. It was named after its inventor, Swiss engineer Jakob Buchli. The drive is a fully spring-loaded

drive Drive or The Drive may refer to: Motoring * Driving, the act of controlling a vehicle * Road trip, a journey on roads Roadways Roadways called "drives" may include: * Driveway, a private road for local access to structures, abbreviated "drive" * ...

, in which each floating axle has an individual motor, that is placed in the spring mounted

locomotive frame A locomotive frame is the structure that forms the backbone of the railway locomotive, giving it strength and supporting the superstructure elements such as a cab, boiler or bodywork. The vast majority of locomotives have had a frame structure ...

. The weight of the driving

motors An engine or motor is a machine designed to convert one or more forms of energy into mechanical energy. Available energy sources include potential energy (e.g. energy of the Earth's gravitational field as exploited in hydroelectric power gene ...

is completely disconnected from the driving wheels, which are exposed to movement of the rails. First used in electric locomotives from the 1920s, the Buchli drive made possible the construction of faster and more powerful locomotives that required larger and heavier

traction motors A traction motor is an electric motor used for propulsion of a vehicle, such as locomotives, electric or hydrogen vehicles, or electric multiple unit trains. Traction motors are used in electrically powered railway vehicles (electric multiple u ...

. The system minimises the impact on

rail track Railway track ( and UIC terminology) or railroad track (), also known as permanent way () or "P way" ( and Indian English), is the structure on a railway or railroad consisting of the rails, fasteners, sleepers (railroad ties in American E ...

s due to the reduction in the overall

unsprung weight The unsprung mass (colloquially unsprung weight) of a vehicle is the mass of the suspension, wheels or tracks (as applicable), and other components directly connected to them. This contrasts with the sprung mass (or weight) supported by the ...

. Although the drive was very successful though the 1930s, it is little used in modern locomotives, having been replaced with smaller, simpler drives that exhibit less imbalance and allow higher speeds.

Construction

In a Buchli drive a driven gear wheel is securely fixed to the

. Inside this gear wheel are two levers, coupled to gear segments that mesh with one another. The other end of the levers is coupled via

universal joint A universal joint (also called a universal coupling or U-joint) is a joint or coupling connecting rigid shafts whose axes are inclined to each other. It is commonly used in shafts that transmit rotary motion. It consists of a pair of hinges ...

s to tension bars, which are then coupled via more universal joints to the driving rail wheel. Vertical movement of the driving wheel results in the gear segments moving due to the internal mechanism, and the driving wheel can move in a horizontal or vertical direction with respect to the gear wheel, while still transferring the momentum of the gear wheel. A disadvantage of the drive was the large number of moving parts, which demanded frequent

lubrication Lubrication is the process or technique of using a lubricant to reduce friction and wear and tear in a contact between two surfaces. The study of lubrication is a discipline in the field of tribology. Lubrication mechanisms such as fluid-lubr ...

and careful maintenance. As a result the Buchli drive system was mainly used on express train locomotives, as there were no other drive systems that gave the same performance at high speeds. However, at higher speeds the drive components became unbalanced, causing issues at speeds over 140 km per hour.

Standard design

The Buchli drive was exported to other rail companies as one sided separate

traction motor A traction motor is an electric motor used for propulsion of a vehicle, such as locomotives, electric vehicle, electric or hydrogen vehicles, or electric multiple unit trains. Traction (engineering), Traction motors are used in electrically powe ...

drive, usually with an inside frame. The motor framework with the wheelset bearing is located between the wheel disks of the driving wheels. The gear wheel, which is housed in an auxiliary frame outside the driving wheels and is surrounded by a protective casing, is on one side of the driving wheels. Each gear wheel is driven by an individual traction motor, which is located above the gear wheel in the locomotive body. With this implementation, a strongly one-sided weight distribution occurs in the underframe through the remote gear wheels. In order to maintain stability of the locomotive on the longitudinal axis, heavy equipment inside the locomotive body must be arranged on the opposite side of the drive equipment. Locomotives with a Buchli drive also typically have an asymmetrical appearance: on one side, the bearings of the drive wheels are visible, on the other side, they are almost completely covered by the wheel cover box of the gear wheels.

Other designs

In addition to the standard implementation, there were also the following variations:

Outside frame

The engine framework with the driving wheel housing is outside the wheel disks of the driving wheels. The driving wheel is enclosed by a quill camped in the locomotive cabinet, on which the gear wheel sits. Examples included the Pennsylvania Railroad O1b, and the

Deutsche Reichsbahn The ''Deutsche Reichsbahn'' (), also known as the German National Railway, the German State Railway, German Reich Railway, and the German Imperial Railway, was the Weimar Republic, German national Rail transport, railway system created after th ...

ET11.01.

Group drive

The motor is arranged between the floating axles. A common pinion or a pinion on both motor end drives the gear wheels of the neighbouring axes. described this design, but vehicles implementing it are not known.

Bilateral drive

The driving wheel is coupled with two gear wheels, and the motor has a pinion on both sides. The taps in the wheel disk are warped about 90 degrees against each other so that the drive imbalance can be reduced. This version of the driver was used for greater driving power. However with this arrangement, there is the danger of mechanical stress in the drive components. Examples included the French express train locomotives: SNCF 2D2 5400, SNCF 2D2 5500, SNCF 2D2 9100.

Two motors per axis

Two driving motors work on one common gear wheel, which is interconnected with a driving wheel. Examples include the Pennsylvania Railroad O1b.

Locomotive with Buchli drive

Nearly 240 locomotives of the SBB with Buchli drive were in use for over sixty years. The SBB Ae 3/6^I class locomotives were in operation from 1921 to 1994. French tracks had 100 express train locomotives using the Buchli drive, in service for fifty years. *

SBB-CFF-FFS 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 government institution, but since 1999 it has been a special stock corpo ...

, Switzerland ** SBB Be 2/5 (Prototype locomotive) ( Deutsch) ** SBB Ae 4/8 (Prototype locomotive) ( Deutsch) ** SBB Ae 3/6^I ** SBB Ae 4/7 ** SBB Ae 8/14 (11801)( Deutsch) *

, Germany ** E 16 (116) ( Deutsch) ** ET 11.01 double railcars Bo'2'+2'Bo'. Constructed in 1938, implementation without frame. The vehicle was rebuilt in the 1960s and the Buchli drive system was removed *

SNCF The Société nationale des chemins de fer français (, , SNCF ) is France's national State-owned enterprise, state-owned railway company. Founded in 1938, it operates the Rail transport in France, country's national rail traffic along with th ...

** SNCF Class 2D2 5400 (mutual drive) ( Français) ** SNCF Class 2D2 5500 (mutual drive) ( Français) ** SNCF Class 2D2 9100 (mutual drive) ( Français) * Indonesian national railway **3000 - four 1'Do1' locomotives for the 1.5 kV

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system, manufactured by SLM and BBC in 1924 and 1926, scrapped 1976 or thereabouts. This locomotive was the first type to get the

Java bogie The Java bogie (, Java-Gestell often in Swiss literature), was a bogie for electric locomotives manufactured by the Swiss Locomotive and Machine Works (SLM). It contained a driving wheel and a trailing wheel. It got its name because it was first ...

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*

Japanese Government Railways The Japanese Government Railways (JGR) was the national rail transport, railway system directly operated by the until 1949. It was a predecessor of Japanese National Railways and the later Japan Railways Group. Name The English name "Japanese ...

**7000 - two (1A)Bo(A1), constructed in 1926, later renumbered as the ED54 class (ja) *

Indian Railways Indian Railways is a state-owned enterprise that is organised as a departmental undertaking of the Ministry of Railways (India), Ministry of Railways of the Government of India and operates India's national railway system. , it manages the fou ...

** EA/1 and EA/2 (later on WCP-1 and WCP-2) - 2BoA2- 22+1 units built in 1928-30 by SLM, Vulcan Foundry and MetroVick. ** EB/1 and EC/1 (later on WCP-3 and WCP-4) - - 1+1 units built in 1928 and 1938.

*

RENFE Renfe (, ), officially Renfe-Operadora, is Spain's national state-owned railway company. It was created in 2005 upon the split of the former Spanish National Railway Network (RENFE) into the Administrador de Infraestructuras Ferroviarias ( ...

**RENFE series 272, ordered by predecessor company NORTE, 12 constructed in 1928 as the Stk for a 1.5 kV supply voltage. * Paulista-Railway, Brazil ** 320, 1Do1, constructed in 1932. *

Czechoslovak State Railways Czechoslovak State Railways (''Československé státní dráhy'' in Czech or ''Československé štátne dráhy'' in Slovak, often abbreviated to ČSD) was the state-owned railway company of Czechoslovakia. The company was founded in 1918 ...

E 465.0 E, or e, is the fifth letter and the second vowel letter of the Latin alphabet, used in the modern English alphabet, the alphabets of other western European languages and others worldwide. Its name in English is ''e'' (pronounced ); plu ...

- 2 Stk 1Do1 locomotive for 1.5 kV supply voltage. Built in 1927 and scrapped in 1962 *

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** Pennsylvania Railroad O1b - 2 Stk 2Bo2 locomotives. Built with inside frame and two driving motors per axle. *

Circumvesuviana Circumvesuviana () is a railway network in the east of the Naples metropolitan area, operated by Ente Autonomo Volturno, EAV. Electrically powered throughout, the system uses the narrow gauge of and operates of route on six lines. It is ...

, Italy **1Do1 locomotive. 5 units 0301 built in 1931 and 0302-0305 built in 1934. All built by Tecnomasio Italiano Brown Boveri.