Side Bearings Preaload Test Benefits

1. Significant maintenance cost saving is produced by qualifing on spot the Resilient Side Bearings.

2. Significant ride quality and safety against derailment improvement is achieved by controlling the Resilient Side Bearing Preload car distribution.

Resilient Side Bearing Preload Test

General

This test objective is to qualify resilient constant contact side bearings preload without removing any parts from the car. The quick and accurate test procedure is required for railway car Shop Inspection.
Before starting the test, make sure the Smart Shoe sensor fit your side bearing characteristics (dimensions, resilient pad distribution and nominal preload). The following Smart Shoe sensor specifications: 20,000 lb nominal load, 1-inch thick, two sitting rods of 1.5 inch long and 2.6 inch apart, steel wings of 2.5 inch wide and 1.5 inch apart should be considered for this test.

Required Tools

1 Two Smart Shoe sensors
2 One-inch +/- 1/16 inch thick spacer for centerbowl
3 Six-inch steel rule

Test Procedure

1 Position the empty car on level track with jacking facility
2. Carefully observe applicable safety rules. Ensure that the car is secure against movement
3 Record the set up height on each side bearing (use 6-inch steel rule or side bearings manufacturer recommended tool)
4 Following the proper procedure detruck one end of the car
5 Inspect Side Bearing metal parts for cracks and elastomer pads for melting; replace in kind
6 If car is equipped with any type of semi-permanent elastomeric centerplate liner, it must be in place when measuring the preload force. Inside the centerplate and on top of the existing liner install 1-inch +/- 1/16 inch thick spacer to compensate for Smart Shoe sensor height
7 With the car body raised, position one Smart Shoe sensor on top cap of the left side bearing. For Side Bearings models featuring exposed elastomeric pads withoutmetallic cup, a 1/4" thick steel plate must be located on top of the elastomericpads. The Smart Shoe sensor shall then be located between this 1/4" plate and the carbody friction plate. To compensate for the plate thickness, an additional 1/4" shim should be added on top of the 1" thick center bowlshim (or one piece of 1 1/4" thick shim). 7. As described above, position the second Smart Shoe sensor on top cap of the right side bearing
8. As described above, position the second Smart Shoe sensor on top cap of the right side bearing
9 Turn on the Smart Shoe or Smart Twin and slowly lower the carbody. Make sure the rods located on one side of the sensor and the wings on the other side are in contact with side bearing and carbody friction plates, respectively
10 Record the Smart Shoe or Smart Twin reading when the car is motionless
11 Detruck the car to remove the centerbowl spacer and both Smart Shoe sensors
12 Follow the same sequence for the side bearings located at the other end of the car
13 Report the records to supervisor at the end of the test