Bogie

Description of a bogie

The essential function of the bogies is to facilitate turning circle. Indeed, the bogies of the vehicle can swivel independently from/to each other, which authorizes weaker radii of curvature, and a more important distance between the Essieu X (than they are driving or carrying).

The load of the vehicle in general rests on the bogie via a central bearing (on the bogie) and of a pivot (interdependent of the frame of the coach) made safe by a mainstay. On the current vehicles, the bogie can slip freely under the case, which improves comfort; one speaks in this case about “fictitious pivot” as on the cars the SNCF of the type “Corail”.

On the locomotive with vapor, one thus increased the number of bogies for better distributing the weight of the engine without multiplying the number of Essieu X driving and thus a too large footing rigid: a Bissel with a Axle then a carrying bogie with two Axle X with front, a partial bogie (in the form of Bissel) even a bogie with the back in addition to the Axle X driving.

The word bogie is a word of English origin which means also convertible, i.e. historically horse-drawn attachment being easily guided.

History

Turning circle of weak ray of increasingly long cars was very quickly a problem for the railway material. The solutions brought were of two orders:

of the Axle X articulated as in the System Arnoux or the Bissel,
of the carriages with weak footing at each end of car.

It is in fact this last solution implemented on the American material which will perdura. The bogies quickly spread with the the United States starting from 1830, because rolling stocks were to accept a way badly posed, and in France, the bogie appears for the first time in 1890 on the towed material. On the locomotive with vapor, the Bissel then the bogie made gradually their appearance as the engines thus became more powerful and increasingly long and more and more doors. These Essieu X only carrying, and is then intended to distribute the load on the way. There existed also the bogie-bissel in which the carrying Essieu is related to the first driving Essieu whose most known bogie-bissel of the type “ Zara was the ”. Another case particuler was the use of bissel with two Essieu X with the back of the machine, the such Hudson.

The numerical nomenclature of the locomotive with vapor is a succession of three digits indicating the number of Essieu X carrying before , then the number of Essieu X driving , then the number of Essieu X carrying postpones . Thus celebrates it ''' Pacific ''' of provision of axles 231 comprises thus two Essieu X carrying out of bogie, three Essieu X driving, and a Essieu in Bissel. An equivalent nomenclature using of the letters for the Essieu X driving is used for the electric locomotive and Diesel loco.

It is only starting from 1950, with the development of the electric locomotive and Diesel loco, that the driving bogie spreads. One then speaks about engines with “total adhesion” with however an exception in the case of A1A A1A where each driving Essieu enters it exists a Essieu distributing the load.

Functions of the bogie

In addition to its role of connection between the Axle X and the case, the bogie ensures the roles of braking, interface between the indication on way and the case, of suspension of the whole of the train, and sometimes of traction. One thus distinguishes two big families from bogies:

driving bogies with Driving S in the case of a direct traction or with the pinions in the case of an indirect traction.
and carrying bogies (not of engine), generally rather dedicated to braking and ensuring the répartion of the loads and guidance.

Each bogie has at least two in general Essieu X except the particular case such:

the Spanish express train “Talgo”, whose cars rest on intermediate bogies with a Essieu by bogie.
coaches for transport of heavy loads where one can count several Essieu X.
some Rail-car S as the Bugatti where one has 5 Essieu X.
the 3 tyred oars of the area Is and the 2 prototype cars of the CF

For the last two cases the augementation of the Essieu X is the consequence of the replacement of the Roue S out of steel by tires. Each vehicle (Locomotive, car, Coach) has its own bogies (generally two), or the bogies are located at horse between two cars (case of the articulated oar S, in particular TGV and Talgo).

Usually, the floor of the vehicle is located above the bogies. However, this rule does not apply to certain types of railway material: trains on two levels or Coach S flattened for cumbersome loads: the floor, or the loading plan, is then flattened between the bogies. There exist Tramway S with ultra-low floor without bogies.

The improvement of the performances of the bogies is an important component to increase reliability, the safety and the comfort of rolling stock.

Acceleration

According to the advance of the way, the bogie is subjected to vertical or transverse forces, respectively vertical acceleration bogie and transverse acceleration bogie.

For the ways managed by the SNCF, the values of acceleration case and bogie are regularly raised by a car equipped especially with Capteur S, the Car Mauzin. Starting from these values, the interventions for the maintenance of the way can be given.

Slide-lathing

The railway Essieu is rigid by nature. Except on the Axle X driving modern, there is no differential. To limit the slip of the Wheel S in the curves, due to the difference of course between the file of rail external and the interior file of rail, the wheels of railroad are truncated and the rails are tilted towards the interior (of 1/20 on traditional line and LGV).

The centrifugal force tends to move the Essieu towards the outside of the curve, which causes to place the external Roue in contact with the rail on its larger circumference, while the interior Roue is in contact on its smaller circumference. The difference of the rolling circumferences corresponds more or less to the difference in linear velocities.

This natural adaptation, which holds place of differential, is more or less opposed by the insufficiencies or excess of cant, according to the speed and the mass of the train.

It also ensures a natural centering of the Essieu on the way. Except in the short radiuss curve, the roll of the Roue never touches the rail. On the ways in alignment, the worn part of the rail makes in general one to two centimetres broad.

This centering is actually perpetual a " recentrage" , in particular at exit of curve with insufficiency or excess of cant. The Essieu X have an oscillating movement which prints with the bogie a rotation movement, known as of " chariotage". This movement is deadened by plates of friction between the cases and the bogies, even by hydraulic dampers (on the TGV).

This movement of slide-lathing can, by friction or " fouettage" , to move the blades of needles. This is why the needles likely to be traversed with more than 40 km/h must be provided with a locking mechanism. This bolt is a mechanical device of nonreversible type: it can be operation by the rod of ordering of the needle, but not by the blade of needle itself.

List bogies of the SNCF

Coaches goods

It are numbered in odd series:

Y 1 Bogie “Diamond” with flat members (style the USA " Archbar")
Y 3 Bogie “Diamond” alternative of braking with shoes external
Y 5 Bogie “Diamond” with steel spars moulded
Y 7 Bogie “ARBEL” or “North-eastern”
Y 19
Y 21
Y 25
Y 27
Y 29
Y 31
Y 37

Cars traveller

They numbered in even series:

X Bogie " Pennsylvania" network of the State
Y or standard TY Bogie " Lits" coaches;
Y 2 standard Bogie OCEM " Pennsylvania"
Y 16 the standard Bogie SNCF " Pennsylvania"
Y 20
Y 24
Y 28
Y 32

See too

Axle
Boudin (railway)
Classification of the engines

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