Roller Non Constant Contact Side Bearing Types Block Constant Contact Metal Cap Non Metal Cap
Linear Cage Telescoping Cylinders Side Bearing Types
Truck Bolster Car Body Wear Plate Preload Setup Height Travel Basic Terminology Constant Contact Standard 5/16” Long 5/8 ”
Setup Height is the distance between the wear plate and bolster pad Rule 62 has condemning limits for different models Important to measure on empty cars on reasonably level track Shims added or removed to adjust setup height Setup Height
Long Travel Roller Assist Standard Travel Side Bearing Types
Functions of a Side Bearing Improve curve negotiation Help in controlling car body roll Increase hunting threshold
Long Travel (LT) equalizes vertical wheel loads entering and exiting curves. VV Curve Negotiation
qPad absorbs energy on each compression qArea within curve is equal to absorbed energy qHelps to dampen car body roll Vertical Hysterisis
At higher speeds, the steering forces will cause the wheel set to over compensate and diverge from equilibrium. What is Hunting?
Side Frame - Pedestal Roof Side Frame - Adapter Lugs Bolster- Inner Column Gibs Side Frame - Anti Rotation Lugs Bolster - Column Gibs Bolster - Shoe Pocket Why Hunting Control is Important to Car Owners – Reduces Excessive Wear!
AAR Circular C-9560 on December 10, 2002 Rule 88.C.3.(18)(m) – Truck Components All units must be equipped with ……. Long-travel Constant-Contact Side Bearings …… conforming to AAR Specification M-948. Effective December 31, 2002. (1) New Cars (2) Rebuilt Cars (3) Extended Service Status Cars (4) Increased Gross Rail Load Cars Long Travel Mandate for New Cars
AAR Circular C-10068 on March 24, 2005 Rule 88.A.15.f – Tank Cars The approved revision to the rule becomes effective on April 1, 2005. AAR Circular C-10271 on February 9, 2006 Rule 90.B.5.i – Flat Cars The approved revision to the rule becomes effective on April 1, 2006 as was suggested in c-10250. Recent Long Travel Mandates
AAR Side Bearing Mandate TTCI Side Bearing Testing - Comprehensive CCSB and Car Type Matrix Rule 62 - New Side Bearing Maintenance and Billing Requirement M-948 - Side Bearing Specification Rewrite
AAR Field Manual Rule 62 Wear limits Setup height criteria Correct repair practices General information Billing and Job codes
Incorrect fasteners can lead to broken housings Yard Inspection