Improved Brake Systems AAR SRI Project Steve Belport AAR Brake Systems Committee

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Brian Walker
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1 Improved Brake Systems AAR SRI Project Steve Belport AAR Brake Systems Committee TTCI, a subsidiary of the AAR, p0

2 Improved Brake System Performance Objective: Improve brake system performance by investigating the root causes of poor performance Demonstrate potential solutions End Product(s): Improved braking, improved brake shoe life, improved wheel life Major Tasks in 2010: Improved truck brake rigging Static and dynamic brake shoe force testing of improved designs Evaluate four candidate remote operated handbrake systems Monitor electronically controlled pneumatic (ECP) brake system performance and reliability TTCI/AAR, 2010, p2

Improved Brake System Performance Asymmetric wheel wear (SRI 2A):

with: Truck & car body brake rigging asymmetries Asymmetric tread wear due

increased track / rail forces / stresses Associated high conicity wheels

3 Improved Brake System Performance Asymmetric wheel wear (SRI 2A): Identified on 134 coal cars in fleet of Mitsui Rail Capital Associated with: Truck & car body brake rigging asymmetries Asymmetric tread wear due to asymmetric location of the shoe on the tread & shoe contact Increase in brake forces? Seems to be endemic to NA fleet Results in: Reduced wheel life Possible increased track / rail forces / stresses Associated high conicity wheels Suggested remedies: Symmetric brake rigging Altered shoe shape Tournay to make extended presentation by telecon to next BSC meeting TTCI/AAR, 2010, p3

4 Improved Brake System Performance Progress: Improved Truck Brake Rigging Demonstrate designs that provide improved distribution of brake shoe forces TAG sourced for ideas and feedback Nine rigging designs for evaluation Tests include: Static shoe force tests conducted June 2010 (8 systems tested) Dynamic shoe force tests fall 2010 Instrumented brake shoes Standard 3-piece truck and M-976 truck Brakes applied/released in moving car Apply brakes in tangent prior to curve, release brakes in tangent following curve Apply brakes in body of curve, release brakes in tangent following curve Apply brakes in tangent prior to curve, release brakes in body of curve TTCI/AAR, 2010, p4

5 1. Base case: normal unit beams Sliding contact between beam and side frame Performance will be used to quantify any improvements in the other designs Commercially available TTCI/AAR, 2010, p5

6 2. Modified unit beams Small tab welded to bottom of beam end extension Minimize reaction moment in side frame Design concept TTCI/AAR, 2010, p6

7 3. Longer unit guide bracket and beam end extension Longer end extension reacts in line with brake force also limits beam droop and taper shoe wear Design concept TTCI/AAR, 2010, p7

8 4. Unit beams with link brake system 4-bar linkage: Restricts beam pitch & lateral motion Reacts moments on beam Commercially available TTCI/AAR, 2010, p8

9 5. Modified unit beams with link brake system 4-bar linkage: Restricts beam pitch and lateral motion Reacts moments on beam Design concept TTCI/AAR, 2010, p9

10 6. Swing hanger beams with link brake system 4-bar linkage: Restricts beam pitch and lateral motion Reacts moments on beam Acts as a safety support for hanger beam Design concept TTCI/AAR, 2010, p10

11 7. Swing hanger beams Supported from swing link to eliminate sliding friction No beam end extension Commercially available TTCI/AAR, 2010, p11

12 8. Swing hanger beams with extension nubs End extension restricts lateral motion and acts as safety support device Design concept Swing link fits here Small end extension TTCI/AAR, 2010, p12

13 9. Swing hanger beams with guides Designed to prevent wear or chatter as it engages Not available for testing by TTCI until September Design concept (US Patent 7,527,131 BI) TTCI/AAR, 2010, p13

14 SRI 5A: Improved Brake System Performance Preliminary static shoe force test results Evaluation based even distribution of shoe forces Swing hangers (#7, #8) performed very well Unit beams (#1A&B, #2, #3) performed reasonably well (new condition) Link systems (#4, #5, #6) and were over-constrained in this test with bent truck levers have had much better results in past with straight levers Static Shoe Force Results Static Shoe Force Results Shoe Force Positive and Negative Percent Variation 25% 20% 15% 10% 5% 0% 5% 10% 15% 20% 1A. Base Case A 1B. Base Case B 2. Modified Unit Beams 3. Long Extensions 4. Unit Beams wlink 5. Modified Beams wlink 6. Swing Hanger wlink 7. Swing Hanger Shoe Force Total Percent Variation 40% 35% 30% 25% 20% 15% 10% 5% 1A. Base Case A 1B. Base Case B 2. Modified Unit Beams 3. Long Extensions 4. Unit Beams wlink 5. Modified Beams wlink 6. Swing Hanger wlink 7. Swing Hanger 25% Brake Cylinder Pressure (psi) 8. Swing Hanger w/ Nubs AAR Criteria (S 401) 0% Brake Cylinder Pressure (psi) 8. Swing Hanger w/ Nubs TTCI/AAR, 2010, p14

Mini Load Cell x 2 10,000 lbs capacity Normal

15 SRI 5A: Improved Brake System Performance Dynamic curving tests with instrumented brake shoes Fall 2010 Instrumented clevis pin 12,500 lbs capacity Friction retarding force Mini Load Cell x 2 10,000 lbs capacity Normal force Top/Bottom force distribution TTCI/AAR, 2010, p15

16 SRI 5A: Improved Brake System Performance Path Forward Improved truck brake rigging Conduct static testing on system #9 when it becomes available Calibrate instrumented brake shoes Conduct dynamic testing, fall 2010 Continue evaluation of four candidate remote operated handbrake systems at FAST Continue to monitor ECP brake system performance and reliability TTCI/AAR, 2010, p16

UPDATE OF TTCI S RESEARCH IN TRACK CONDITION TESTING AND INSPECTION. Dingqing Li, Randy Thompson, and Semih Kalay

Dingqing Li 1 UPDATE OF TTCI S RESEARCH IN TRACK CONDITION TESTING AND INSPECTION Dingqing Li, Randy Thompson, and Semih Kalay Transportation Technology Center, Inc. Pueblo, CO 81001 Phone: (719) 584-0740,