of the armature shaft indicated no distress from movement of the locking screws.[1]
The failed bearings had been reconditioned before they were installed in the traction motor. A reconditioned bearing is one that has been removed from a traction motor and returned to the manufacturer’s plant for reconditioning. All parts of the hearing are inspected, gauged, and any defective part is replaced with a new part The bearing parts are stamped to identify them as being reconditioned par ts The bearing is then returned to the original owner with the same guarantee as that given for a new hearing The reconditioned bearings are coated and packaged in a manner similar to that for new bearings. After a bearing is removed from the package, it is difficult to determine whether it is new or reconditioned
The component parts of the roller bearings are marked with serial numbers and other identifying information when manufactured, and with additional markings when recon- ditioned. the SKF and ICRR companies do not maintain records by serial numbers of the bearings purchased. From the markings found on the pinion—end bearing and the SKF records, it was determined that the bearings had been returned to SKF on December 8, 1970, were reconditioned and returned on February 5, 1971.
I History of the Traction Motor
The traction motor which propelled the lead wheels of the rear truck of unit 4031 contained serial no. 53F476 and was built by EMD in June 1953 as a type D—37B. It was rebuilt by the Chandeysson Electric Company of St Louis, Missouri, and upgraded to a class D—77 motor The upgrading consisted, in part, of electrical improvements which qualified the motor for heavier duty operation than its original design would have permitted. The rebuilt motor was sent to the Paducah shops in November 1970
The tr action motor was installed in a type GP-40
locomotive unit on November 11, 1970 On
January 25, 1971, after being in service for
21,132 miles, the motor was removed because of
electrical trouble and was returned to the
Chandeysson Electric Company under warranty
on February 17, 1971. During repairs, the
reconditioned armature bearings (see above)
were installed and the motor was returned to the
Woodcrest shop on February 24, 1971. The
traction motor was installed in unit 4031 on
April 11, 1971. From the date of the installation
to the time of failure, unit 4031 traveled a
distance of 33,127 miles
J. The Chandeysson Electric Company
The main business of the Chandeysson Electric Company is the rebuilding of diesel- electric locomotive traction motors and genera- tors. It is not a railroad-operated company, but it is associated with Illinois Central Industries Various railroads, in addition to the ICRR, send traction motors and generators to the company for repairs.
The methods and practices of the company were observed as part of the investigation of this accident Cyprina, a sodium—based grease, was used to lubricate the sealed armature bearings Quantity was determined by weight and the cyprina was distributed evenly throughout the bearing cavity Precautions were taken to preclude the entrance of dirt and other foreign material during the assembly of the bearing. Radial gauges calibrated from 0 001 to 0 100 were used to measure the permitted tolerances after the bearings were installed on the armature. Tolerances measured were between .003 and .012 inches.
The serial numbers of the bearings were recorded on the repair form, but a separate record of these numbers was not maintained.
After the traction motor was completed, noise and vibration tests were conducted The motor Was operated at three speeds. At each speed an employee listened for noise produced
by the bearings and placed his hand on the
- ↑ Appendix D contains photographs of wear and marks on parts of the bearing assembly
