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of the speed regulator; however, at the start of the start, a pneumatic contactor modifies the excitation resistance of the exciter. The driver operates a pressure reducing valve, which applies air pressure to the servomotor, increasing as the speed to be imposed on the diesel engine increases. This highly sensitive control method, thanks to the use of meiribrane devices, allows two locomotives to be operated in a coupled configuration (2).
The entire locomotive (driver's cab, engine hood, clutch cabinet, registration number, etc.) is electrically illuminated, as are the front and rear headlights and the position lights. This lighting is provided under the voltage of 130 V, the battery voltage.

AIR COMPRESSOR AND BRAKES

A two-stage air compressor supplies the necessary air:
- to the braking system, which includes an automatic brake circuit on the one hand, and a direct circuit braking only the locomotive on the other.
- to the control devices (Fig. 4);

SAFETY DEVICES

The locomotive is equipped with various safety devices:
- an automatic diesel shutoff valve in the event of an abnormal drop in oil pressure;
- a slip protection system, consisting of a differential relay which, when energized during wheel slip, reduces the air pressure in the control line of the oil regulator spring of the Diesel engine and thus lowers the engine speed, and therefore the power supplied by it; when the slippage is over, the diesel engine speed automatically returns to the value corresponding to the

Fig. 4. - View of the driver's cab.

position of the throttle lever; located in the driver's cab, a speed limiter and alerts the engine's engine when the throttle valve is released.

(2) For this purpose, the two engines are connected by a 12-pin electrical circuit and by air terminals (control of the diesel governors, main trim).