A monomotor bogie (french: bogie monomoteur) is a form of traction

bogie A bogie ( ) (in some senses called a truck in North American English) is a chassis or framework that carries a wheelset, attached to a vehicle—a modular subassembly of wheels and axles. Bogies take various forms in various modes of transp ...

used for 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 or a supercapacitor. Locomotives with on-board fuelled prime movers, such as diesel engines or gas ...

diesel-electric locomotive A diesel locomotive is a type of railway locomotive in which the prime mover (locomotive), prime mover is a diesel engine. Several types of diesel locomotives have been developed, differing mainly in the means by which mechanical power is conv ...

. It is distinguished by having a single

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

on each bogie.

Development

The first electric locomotives used large diameter

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, mounted rigidly on their

frame A frame is often a structural system that supports other components of a physical construction and/or steel frame that limits the construction's extent. Frame and FRAME may also refer to: Physical objects In building construction *Framing (con ...

s and using

jackshaft 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 ...

drives 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 carry their torque to the

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. This increased their

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 ...

and limited their maximum speed, despite the greater power of electric locomotives.

Leading trucks

To achieve a higher speed, locomotives began using wheel arrangements such as 2'Do2' (AAR: 2-Do-2), with the

SNCF Class 2D2 5500 The 2D2 5500 were electric locomotives operated by the Compagnie du chemin de fer de Paris à Orléans, then SNCF in France, in operation from 1933 to 1980. Design and operation This class originated on the PO with the two class locomotives ...

This used leading (and trailing)

pony truck A Bissell or Bissel truck (also Bissel bogie or Pony truck) is a single-axle bogie which pivots towards the centre of a steam locomotive to enable it to negotiate curves more easily. Invented in 1857 by and usually then known as a ''pony truck' ...

s or

s to provide stability at high speed, with individual

s for each axle, avoiding the weight of the coupling rods. Suspension travel for each axle was achieved with a

Buchli drive The Buchli drive is a transmission system used in electric locomotives. It was named after its inventor, Swiss engineer Jakob Buchli. The drive is a fully spring-loaded drive, in which each floating axle has an individual motor, that is placed in ...

on each axle. Unlike the original Swiss practice with a Buchli drive on one end of the axle, the French locomotives used a double-ended drive. This was later given as a reason for the low wear rates experienced with them. These locomotives first appeared during the 1930s with the 2D2 5500, and later during the post-war push for

electrification 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. The broad meaning of the term, such as in the history of technology, economic histor ...

the

SNCF Class 2D2 9100 The Société nationale des chemins de fer français (; abbreviated as SNCF ; French for "National society of French railroads") is France's national state-owned railway company. Founded in 1938, it operates the country's national rail traffi ...

(1950).

Bogies

Shortly after the 9100 class, the French absorbed another new Swiss idea, that of the high-speed double-bogie locomotive. Previous French Bo-Bo locomotives had been considered suitable only for medium speeds, with the pony truck and rigid frame used for express passenger service. The Swiss Re 4/4^I of 1946 achieved speeds of up to , owing to the advanced design of its bogies. New classes were built for French railways, embodying these principles. Two 1,500 V DC prototype Co-Co locomotives for the

SNCF Class CC 7100 SNCF's CC 7100 class are part of a series of electric locomotives built by Alsthom. The prototype 'CC 7000' (7001 & 7002) were built in 1949 and the production series locomotives CC 7101-CC 7158 followed during 1952–1955. Two of the class are n ...

(1952) were built by

Alsthom Alstom SA is a French multinational rolling stock manufacturer operating worldwide in rail transport markets, active in the fields of passenger transportation, signalling, and locomotives, with products including the AGV, TGV, Eurostar, Avelia ...

, the first prototypes being tested from 1949. These locomotives had conventional per-axle traction motors. During tests in 1954 they achieved extremely high test speeds of , which have not yet been surpassed by locomotive-hauled trains.

Monomotor bogies

SNCF Class BB 16500 (1962)

SNCF Class BB 7200 The SNCF Class BB 7200 is a 1.5 kV DC electric locomotive operated by the SNCF in France. It is the DC version of the 'Nez Cassé' family of locomotives built between 1976 and 1985 by Alstom. They are rated for of continuous power. SNCF Cl ...

(1967) This was the first of the '

Nez Cassé The Nez Cassé series of locomotives is a large family of electric and diesel locomotives intended primarily for fast passenger service on the French SNCF railway system. Produced by Alsthom for use under multiple electrification networks and un-el ...

' designs, by

Paul Arzens Paul Arzens (28 August 1903 – 2 February 1990) was a French industrial designer of railway locomotives and motor cars. Arzens was born in Paris, at an address along the on the northern side of the city. As a young man he studied at the � ...

Class CC 40100 (1964), a large quad-voltage locomotive, requiring a C'C' layout with three axle bogies.

Use

Monomotor bogies are widely used in France, for designs by

Alstom Alstom SA is a French multinational rolling stock manufacturer operating worldwide in rail transport markets, active in the fields of passenger transportation, signalling, and locomotives, with products including the AGV, TGV, Eurostar, Avelia ...

. They were a particular feature of the '

' family of locomotives, designed by

Examples

DC * SNCF Class BB 15000 AC *

SNCF Class BB 22200 The BB 22200 is a class of electric locomotives in service with the French railways SNCF, built by Alstom between 1976 and 1986. They are a dual voltage version (1500 V DC and 25 kV 50 Hz AC) of the BB 7200 and BB 15000 classes.The designation " ...

Dual-voltage, combining the attributes of both BB 7200 and BB 15000 (7200 + 15000 = 22200) *

SNCF Class BB 26000 The SNCF BB 26000 locomotives are a class of dual voltage, four axle B'B' electric locomotives capable of a top speed of 200 km/h built by GEC Alsthom between 1988 and 1998 for SNCF. The locomotives are also commonly known as the ''Sybics''. ...

NS Class 1600 The NS Class 1600 is a type of B′B′ electric locomotive built by Alstom between 1980 and 1983 based on the SNCF Class BB 7200, and in use by the Dutch Railways since 1981. They were styled by the French industrial designer Paul Arzens. The ...

Dutch version of the

FS Class E.632 The FS E.632 and E.633 are two classes of Italian railways electric locomotives. They were introduced in the course of the 1980s. The locomotives are nicknamed ''Tigre'' ("tiger"). History The E.632/E.633 were the first Italian locomotives to ...

(Italian)

References

Bibliography

* {{SNCF locos Locomotive parts