MARTS Presentation on Brake System Performance October 2010

7/29/2019 MARTS Presentation on Brake System Performance October 2010

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TTCI, a subsidiary of the AAR, 2010. p0

I mproved Brake SystemsAAR SRI Proj ect

St eve Belpor tAAR Brake Systems Commit t ee


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TTCI/AAR, 2010, p2

I mproved Brake Syst em Perform ance

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 systemperformance and reliability


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TTCI/AAR, 2010, p3


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 & shoecontact

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 extendedpresentation by telecon tonext BSC meeting


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Progress: Improved Truck Brake RiggingDemonstrate 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 tangentfollowing 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


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Rigging Designs

1. Base case: normal unit beams

Sliding contact between beam and side frame

Performance will be used to quantify any improvementsin the other designs

Commercially available


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Rigging Designs

2. Modified unit beams

Small tab welded to bottom of beam end extension

Minimize reaction moment in side frame Design concept


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Rigging Designs

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


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4. Unit beams with link brake system4-bar linkage:

Restricts beam pitch & lateral motion

Reacts moments on beam Commercially available

Rigging Designs


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5. Modified unit beams with link brake system4-bar linkage:

Restricts beam pitch and lateral motion

Reacts moments on beam Design concept

Rigging Designs


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6. Swing hanger beams with link brake system4-bar linkage:

Restricts beam pitch and lateral motion

Reacts moments on beam Acts as a safety support for hanger beam

Design concept

Rigging Designs


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Rigging Designs

7. Swing hanger beams

Supported from swing link toeliminate sliding friction

No beam end extension

Commercially available


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TTCI/AAR, 2010, p12

Rigging Designs

8. Swing hanger beams with extension nubs End extension restricts lateral motion and acts as

safety support device

Design concept Swinglink fitshere

Small endextension


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TTCI/AAR, 2010, p13

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)

Rigging Designs


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TTCI/AAR, 2010, p14

SRI 5A: I mproved Brake Syst em 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 benttruck levers have had much better results in past with straight levers

0%

5%

10%

15%

20%

25%

30%

35%

40%

0 20 40 60 80

ShoeForceTotalP

ercentVariation

BrakeCylinderPressure(psi)

StaticShoeForceResults

1A.BaseCaseA

1B.BaseCaseB

2.ModifiedUnitBeams

3.LongExtensions

4.UnitBeamswLink

5.ModifiedBeamswLink

6.SwingHangerwLink

7.SwingHanger

8.SwingHangerw/Nubs25%

20%

15%

10%

5%

0%

5%

10%

15%

20%

25%

0 20 40 60 80

ShoeForcePositiv

eand

Negative

PercentVa

riation

BrakeCylinderPressure(psi)

StaticShoeForceResults1A.

Base

Case

A

1B.BaseCaseB

2.ModifiedUnitBeams

3.LongExtensions

4.UnitBeamswLink

5.ModifiedBeams

wLink

6.SwingHangerwLink

7.SwingHanger

8.SwingHangerw/

Nubs

AARCriteria(S401)


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TTCI/AAR, 2010, p15

SRI 5A: I mproved Brake Syst em Performance

Dynamic curving tests with instrumented brake shoes Fall 2010

Instrumented clevis pin

Mini Load Cell x 2 10,000 lbs capacity

Normal force Top/Bottom forcedistribution

12,500 lbs capacity Friction retarding force

SRI 5A: I mproved Brake Syst em


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TTCI/AAR, 2010, p16

SRI 5A: I mproved Brake Syst emPerformance

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 handbrakesystems at FAST

Continue to monitor ECP brake system performance and reliability

Documents

MARTS Presentation on Brake System Performance October 2010