Series tractors

In fact, this new machine was the result of combining the powertrain of two Y tractors on the same chassis. The assembly was synchronized by a device, developed and patented by the C.F.D., called the Asynchro transmission. This system made it possible to use two separate engines, each controlling a bogie with two axles connected by a connecting rod. On the unit in service in the Vivarais, these had been added to limit the weight as much as possible, due to the weakness of the track.

The synchronisation of the two groups was ensured by means of a hydraulically controlled gearbox and a set of free wheels. Traction could also be provided by means of a single engine, thus allowing great flexibility of use and limiting line distress.

Description of the tractor type BB 400

Tractors of this type were equipped with two 207-horsepower Poyaud engines, each housed under a hood at each end of the chassis and cooled by a powerful fan occupying the entire front end of the tractor.

A central raised cab with panoramic vision contained all the controls under a functional console.

The fuel tank was located under the cabin and the auxiliaries were housed under the hood of each unit. The chassis and buffer ties were designed for both narrow and normal track operation.

Access to the engines was from the extremities and to the cabin from the middle of the side face, using a set of steps and handrails.

The unit assigned to the Cheylard was painted light green with a yellow stripe on top of the engine cowls and chassis. The chassis was a darker green colour. The large bumper crossbars were painted yellow bordered with red and were marked 040-003 on the right and the Company initials on the left. The rectangular builder's plate was attached to the chassis at the level of the cab.

Delivery and assignments of the BB 400 tractor type

Initially intended to equip the Vivarais network, the first two tractors were sold in 1962 to the Société Générale des Chemins de Fer Economiques (S.E.) for its P.O.C. leased network. The C.F.D. immediately began construction of a third unit in 1963 and shipped it to Le Cheylard on 15 October 1963.

Tried on the section of the Cheylard at Dunières, it behaved very well there, but its too slow speed made it confine itself to the service of goods and market trains of the line from Cheylard to Tournon. Particularly appreciated for its great towing abilities, it was particularly suitable for towing heavy timber trains between Lamastre and Tournon.

Due to the uncertainty surrounding the continued operation of the network, the construction of the second model was postponed and then cancelled in 1968.

When the network was closed, the 003 was parked waiting for a decision on its future. Belonging to the State, it was finally allocated to the Chemins de Fer de Provence network in June 1969. A few years later it was transferred to Corsica.

source : MTVS 1989-1