HEATING, LIGHTING, AND AIR CONDITIONING
an underframe suspension, gives constant belt tension
for 8 inches of generator travel.
The three commonly used systems for train lighting are
(c) The suspension must be lubricated
the axle-generator system, the head-end system, and
properly to prevent wear of the parts and loss of proper
the storage system.
alinement Grease may be forced through the bronze
bearings in which ample grease space is provided
a. Axle-Generator System. The axle-generator
Grease can be applied by a compression cup installed in
system is the one most frequently used for train lighting.
the supporting shaft and bearing or by a grease gun if
In this system the drive is the means of transmitting
the proper fittings are applied to the suspension. As the
power from the axle of a railway car to the generator.
The types most generally used are the belt drive and the
preferable to cup grease.
direct drive. The belt drive is the earlier development
and is still found on many cars Exposure of the
(d) When necessary to remove the
operating mechanism to severe winter weather and to
generator from the suspension, block up the generator
the dust and grit encountered in hot, dry weather creates
to take the weight off the suspension shaft.
problems in wear, loss of tension, and general
maintenance that have been impossible to overcome.
Loosen the lockscrew and remove the grease cap at one
Moreover, the larger generators demanded by air
end. Then insert a bolt into the tapped hole in the end
conditioning have made the belt drive impractical. The
of the suspension shaft and pull the shaft out of the
more efficient direct drive does not present these
bearings and lugs. The Insertion of the bolt provides a
problems, since a shaft replaces the belt. An additional
means of applying a drawing force; or if the shaft is free,
advantage of the direct drive is that power transmission
it serves as a handhold with which the shaft may be
losses are relatively low.
withdrawn. If the supporting shaft resists efforts to
withdraw it, remove it by further disassembly of the
(1) Belt drive (fig 10-1).
(a) The driving pulleys or sheaves are
(2) Direct drive.
affixed to the car axle, and the driven pulleys are
secured to the armature shaft of the generator. Over
(a) Direct drive generally employs a
this set of pulleys, an endless flat belt or a V-belt is
minimum number of moving parts. In one type, all
installed, and as the car axle rotates, the belt transfers
wearing parts run in a constant bath of light oil where
this power to the generator The combined V-belt and
they are completely sealed and protected from ballast,
gear drive employes four or six V-belts to drive a set of
dirt, water, snow, Ice, or other foreign matter. This type
sheaves mounted on a gearbox hung from the truck end
of drive transmits power from the axle of a railway car to
sill. These sheaves drive a gear shaft which, by means
a generator through a mechanism consisting of a gear
of a bevel gear, drives the generator mounted on the car
unit, a propeller shaft, and a clutch This drive consists of
body through a propeller shaft equipped with universal
an unsplit hypoid gear mounted in a gearcase ,on a
and slip Joints.
pinion connected to a propeller shaft suspended
(b) A spring arrangement gives
practically constant belt tension throughout any
movement of the generator caused by belt stretch or by
the car's rounding a curve. This arrangement, termed