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 B. Method of Operation

Trains moving with the current of traffic are operated by timetable, by train orders, and by cab signals of an automatic, continuous, inductive train-stop system Wayside signals are not used The cab signals can indicate only proceed (green) or proceed at restricted speed (red)

The rules and regulations of the ICRR's operating department require all train crew-members to inspect the train as frequently as possible, giving special attention to sliding wheels and other defective conditions which might endanger the movement of the train Station employees, including operators, are required to be out of buildings and on the ground or station platforms when trains are passing, in order to inspect for defects. The station employees are required further to convey the results of their inspections to the traincrew by signals.

In addition to the rules of the operating department, engineers on the ICRR are required to be familiar with the contents of booklets furnished by the Electro-Motive Division (EMD) of the General Motors Corporation on the operation of various designs of EMD-built loco- motive units The following requirements are contained in one of these booklets which is titled "Engineman's Operating Manual Model E8":

"Wheel Slip Relay The wheel slip relay is located in the electrical control cabinet, behind the power contactors. If one pair of wheels should slip while locomotive is under power, this relay will pick up, lighting the wheel slip light intermittently to warm engineman as the wheels slip, stop slipping and slip again. The throttle should be reduced to stop slipping, and sand applied to prevent slipping when throttle is reopened.

"Alarm Indications For One Pair of Wheels Sliding if one pair of Wheels should slide when starting a train, the wheel slip light will flash on and off intermittently, but as the train speed increases, the light will stay on more or less continuously, and will not go out when the throttle is reduced and sand applied. The light will go out when throttle is closed to idle.

Under this condition, the engine crew should make an immediate investigation to determine the cause The wheels may be sliding due to a locked brake, a broken gear tooth wedged between the pinion and ring gear, or a motor hearing may have seized

IF A POWER PLANT IS ISOLATED BE— CAUSE OF REPEATED WHEEL SLIP ALLOWED TO REMAIN IN THE LOCO- MOTIVE CONSIST UNLESS IT IS CERTAIN THAT ALL OF ITS WHEELS ROTATE FREELY."
 * * * THAT UNIT SHOULD NOT BE

Further, trip or daily inspection is required of all locomotive units by the Code of Federal Regulations (CFR), Title 49, Section 230.203.2.

C Description of Locomotive Unit 4031

Diesel electric unit 4031 was an EMD, E-8A, car-body type, rated at 2,250 horsepower and built in June 1952. Its total weight was 323,320 pounds The control compartment, located in the forward section, had a rounded nose in front of and below it. The unit had two six-wheeled roller—bearing trucks. (See Figure 2.) Each of the two outside pairs of wheels of each truck was propelled by a traction motor mounted between the axle of the wheels and a crossmember of the truck The motor, which was supported on the axle by two friction type suspension bearings and on the truck frame by a rubber nose suspension pack, drove the wheels by means of a direct connection between a 25-tooth pinion gear mounted on the traction motor and a 52-tooth ring gear mounted on the axle (See