(5) GE 44 Ton Locomotive.
27,000 lbs. starting tractive effort at 30 % adhesion
9,000 lbs. continuous tractive effort at 10 mph
Max. operating speed - 20 mph
Min. curve radius - 50 ft.
Weight - 88,000 lbs.
b. Locomotive Propulsion and Braking Systems.
(1) Power Generation System. The Navy's equipment fleet for the movement of
railcars consists of diesel-electric locomotives, along with a few car movers at select locations.
Diesel-electric locomotives use diesel engines coupled to a generator or alternator to produce dc
current that powers dc traction motors located on the locomotives' axles. Locomotives are both
one- and two-diesel engine designs. Some can only be operated independently, and others can be
operated together in multiple unit (MU) service. In MU service, the coupled units are all
controlled by only one of the units. Some units also have a road/switch capability that changes
the operating characteristics of the unit depending on the use. When locomotives are
rehabilitated, current policy is to standardize all locomotives to the 26-L series brake system, or
better, and the AAR control stand. See Figures 2-14 and 2-15 for pictures of a typical 26-L series
brake and AAR control stand.
(2) Locomotive Traction system. Diesel-electric engines are controlled by a governor
that maintains a constant engine speed and a load regulator that maintains constant power output
for each power setting selected by the operator. The actual tractive effort transferred to the rail
may be limited to less than the power setting by reduced adhesion due to such factors as
contaminated rail (grease, grass, water, etc.) and lack of sand applied to the rail. Wheel slip will
occur in these cases, and on certain locomotives power output is automatically reduced for
predefined periods of time until wheel slip is corrected.
(3) Locomotive Brake system. Each locomotive has an independent and automatic air
brake valve and a mechanically operated hand brake.
The independent brake controls only the brake cylinders on the locomotive. It is the primary way
of reducing the locomotive speed when the locomotive is being operated with no cars.
The automatic brake valve controls both the car(s) and locomotive(s) brakes and is the primary
means of reducing train speed. The locomotive brakes are bailed off, (released), by the operator
until shortly before the complete stop.
The hand brake is used to secure the locomotive any time it is left unattended or attempts to stop
the locomotive in an emergency if the air brakes fail to function.
Navy locomotives are equipped with various brake systems (6RL, 24RL, 26L series, etc.) See
Figure 2-16 for a schematic of a typical series 26-L locomotive air brake system.
2 - 13