TRACTION MOTOR GEAR LUBRICATION REQUIREMENTS AND DEVELOPMENTS

The basic arrangement of the final drive gear system of domestic main line diesel electric locomotives has remained unchanged over the years. During this same time period, the ratings of these locomotives and demands on the gear train have increased considerably. Due to space limitations, interchangeability and retrofit requirements, the changes made to handle the increased power involved subtle but significant changes to gearing, gear case design and the gear lubricant. The purpose of this paper is to present some of the developments in the above areas which include metallurgical improvements, gear geometry changes, and lubricant specifications which the author's company has recently revised by changing from a sodium soap to a lithium soap thickened grease. The new specification also calls for minimum Load Wear Index and Weld Point values that require the use of EP additives. The reasons for adopting the new lubricant specification are presented with a discussion of items where additional development work is required to provide further improvement in gearing and gear lubrication.