The general characteristics of the tractor 400hp 34t
- Length excluding buffer 10 m
- Wheelbase 4 m 92
- Maximum height 3 m 48
- Overall width 3 m
- Weight without empty ballast 33 t
- Weight without ballast 34 t
In order to reduce the cost price per tonne-kilometre on the branch lines, the Departmental Railway Company decided to build 400 hp, 34-tonne diesel tractors.
Detailed description of each component of the tractor 400hp 34t
The chassis of the 400hp 34t tractor
The frame has two 30 mm sheet metal longitudinal members strongly braced in the centre by means of a large cross-member giving it very high rigidity.
At the ends there is a double consisting of a first box which is integral with the frame, a second one is attached and carries the coupling and the buffer; all these and cross members are riveted or welded, as the case may be, in order to lower the construction price.
A fully welded 200 mm U- and I-iron subframe is bolted to the actual chassis. This subframe is very rigid in plan and all the engine and transmission components as well as the cab are attached to it. The central I-iron longitudinally divides the tractor in two, each of these halves containing a driving line (engine, transmission). The tractor is therefore symmetrical in relation to an axis placed vertically in its centre.
The axles of the 400 hp 34t tractor
They have solid sail wheels with solid tires with a rolling diameter of 1.05 m.
Cast steel axle boxes are equipped with S.K.F. roller bearings to reduce maintenance
The suspension and brake linkage of the tractor 400hp 34t
For unification purposes, the suspension has been chosen identical to that of the 150hp unified tractors
The same was true for all parts of the brake rigging that could be used without modification.
Tractor engine 400hp 34t
The Willème-Diesel engine type F 8 M 517 R is a 4-stroke pre-combustion chamber engine.
Characteristics of the Willème-Diesel engine
- Its general characteristics are as follows:
- Number of cylinders 8
- Bore in mm130
- Stroke in mm 170
- Total displacement in cm3 18,050
- Effective power in hp 200/225
- Maximum rpm 1,600
- Minimum load speed 450
- Maximum torque in m/kg 101
- Speed at maximum torque 900/1,250
- Volumetric ratio 18/1
- Final compression ratio in kg/cm 46.7
- Minimum consumption per hp/h 183 g
- Weight of complete motor in kg 1,100
All the parts making up this engine, except for the crankshaft, camshaft and engine block, are the same as those of other types of engines of the same brand 4 and 6 cylinders which are very common on road vehicles, including liners, pistons, connecting rods, bearings, cylinder heads, valves, etc...
Thanks to this special feature, the cost price of repairs can be lowered through series production.
This engine has a Bosch-Lavalette injection pump of the conventional type.
The governor is modified to allow the engine to give 67% of its maximum torque at 500 rpm.
Starting is carried out at 24 volts by means of 2 Bosch-Lavalette 6 hp starters. This arrangement ensures excellent starts even in cold weather'
Each motor is equipped with a Bosch-Lavalette 24-volt 300-watt dynamo. The electrical installation for each motor is thus similar to that of a heavy-duty truck.
Cooling of the 400 hp 34t tractor engine
Each engine is independently cooled by :
1° a water radiator composed of two elements evacuating 104 500 calories per hour ;
2° an oil heater placed in front of the water elements evacuating 11,400 calories per hour.
These two radiators are mounted on the front of each hood.
Each engine drives a Boirault turbine that ventilates the radiators via a pulley wedged in front of the crankshaft by means of 4 "Texrope" belts. This turbine gives a flow rate of 5,700 m3 per second and absorbs 5.4 hp at I 300 rpm.
The turbine mounted on ball bearings is rigidly centred in a cast aluminium nozzle and rotated so that the clearance between the tips of the blades and the nozzle is of the order of 1 to 2 mm necessary for good efficiency.
The hot air is discharged to the side and rear of each hood so that when reversing, the hot air does not end up in front of the cooling elements again.
The oil circulation in the cooling radiator is ensured without pressure by means of a small gear pump driven from the water pump shaft by means of a "Texrope" belt. The oil circuit is designed in such a way that, in the event of leaks in the cooling circuit, the pump stops sucking when the level in the oil sump falls below the safety level.
source : Excerpt from the Revue Générale des Chemins de fer N° of September 1950
