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 tolerances required to be within a range of from 0.003 to 0.012 inches is not considered good practice. Whereas this gauge can measure the tolerances, the movement of the dial is so small that it can easily be misread. A more sensitive gauge calibrated, for an example, from 0.001 to 0.050 or even 0.001 to 0.025 would portray better the situation

The type of grease and the method used to determine the amount of grease were found to comply with the specifications The method of application ensured that adequate lubrication would be provided the bearing. Precautions were being taken also to prevent the admission of any foreign material during the assembly operation

Although the final tests of the traction motors were performed as prescribed by the builder and by the railroads, it is believed that a more reliable method should be adopted. The results of the noise and vibration tests depend strictly on the judgement Of the operator The training or the ability of the operator to apply his knowledge could affect significantly the results of such tests. As can be noted in the report of the tests conducted on the failed traction motor in this accident, the operator has only two choices to make: passed or failed. If the level of noise and of vibration were meas- ured by instrument and the acceptance or rejection of a motor based on these measure— ments, a much improved final test would result, and a more objective standard could be estab- lished

The improper reporting of the reconditioned bearings as new bearings did not contribute to the failure of the hearings in this case However, if a better means were used to identify the difference between a new and a reconditioned hearing it would benefit both the bearing manufacturer and the repair company. The confusion of the similarity of the packaging of the two bearings would be eliminated

E. The Effect of the Blocked Reverser and the lnoperative Wheel-Slip Device

When locomotive units were first put into service, the ICRR blocked the power reverser in neutral position when they were required to move a locomotive unit with an engine shut down, but later the practice was believed to be unnecessary and instructions were issued ac- cordingly. The New Orleans Union Passenger Terminal Company apparently believes that the additional protection is still necessary and blocks the reverser when moving a locomotive unit with an engine shut down. With the power reverser of the No. 2 circuit of unit 4031 blocked in neutral position, power could not be supplied to the traction motors of the rear truck. With no power to the traction motors, the wheel-slip protection device was inoperative Even though the wheels were not receiving power, many of the same factors that could cause the wheels to lock and slide still existed.

The middle wheel of the six—wheel truck is not powered and, therefore, is not provided with wheel-slip protection at any time. This wheel could lock and slide due to defective wheel bearings or stuck brakes and the engineer would not receive an indication of the problem

If the wheel-slip protection device had been operative on unit 4031 on June 10, 1971, the engineer would have received a warning in the control compartment by means of the wheel-slip light before train No 1 arrived at Mason The indication of the sliding wheel would have occurred more than 27 miles north of the accident point The indicator light would have remained illuminated and indicated a continuously sliding wheel The engineer was well versed on the instructions and knew what was required in this situation.

There is no doubt that if the engineer had received the warning, he would have stopped the train, examined the locomotive, and found that the wheels had slid flat The engine crew could have determined easily that the wheel was locked.

F Repairs to Unit 4031 at Woodcrest Shop after Arrival on June 7, 1971

Even though unit 4031 arrived at Chicago without advance notice that the reverser was blocked, at least one engineer's locomotive 25