Tanks

low-pressure cylinders compress air which then passes through a cooling

system to a high-pressure cylinder that compresses it still further before

feeding the air to the main reservoir. This reservoir is kept at a pressure

of 125 to 140 pounds.

2.6. TANKS

Both fuel and water tanks are carried on a diesel-electric locomotive.

The fuel tank, usually suspended beneath the underframe between trucks,

contains fuel oil for operating the diesel engine. Note the parts numbered

35 and 36 on figure 2.1.

A water-expansion tank containing water for

cooling the engine is located at the highest point in the engine-cooling

water system, the part numbered 19 on figure 2.1. This system is designed

to carry away and disperse the excess heat generated in the engine.

2.7. TRUCKS

The main function of the trucks is to provide a connection between the

axles and wheels and the locomotive itself.

The trucks must carry the

weight of the locomotive superstructure and distribute it through the wheels

to the rails. They also absorb lateral thrusts and ride over uneven rails

without excessively tilting and swaying the locomotive.

The trucks also

provide mountings for the brake rigging and traction motors.

Army diesel-electric locomotives have either two 6-wheel swivel 3-

motor trucks or two 4-wheel swivel 2-motor trucks. Figure 2.5 shows a 4-

wheel swivel 2-motor truck used on the 0-4-4-0 diesel-electric locomotive.

The main difference between the 4-wheel and the 6-wheel truck is that the

weight of the locomotive is distributed over a wider surface by a 6-wheel

one; therefore, it has a greater working surface on the rails, giving the

locomotive more tractive effort or pulling power.

2.8. SUMMARY

A diesel-electric locomotive is made up of many complex parts.

Is

internal combustion diesel engine burns diesel fuel oil ignited by the heat

of compressed air within a cylinder, a process known as compression

ignition. The main generator is connected to the engine, and its mechanical

energy output turns the generator to produce the electric current needed to

power the traction motors that turn the locomotive's wheels.

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