Low-Impact Special Trackwork Research at Transportation Technology Center, Inc. David D. Davis Transportation Technology Center, Inc 2009 TRB Annual Meeting - 1 Transportation Technology Center, Inc., a subsidiary of the Association of American Railroads, 2009
Low Impact Special Trackwork for Heavy Haul Freight Operations Background: Heavy Axle Loads Compelling Economics Effects of wheel loads on special trackwork Third leading track cause of accidents Cost Center 10-100 100 x more expensive to operate than conventional track Capacity Stealer many condition related speed restrictions. >$500M per year Performance improvements under HAL 50% reduction in maintenance 100%+ increase in service life 2009 TRB Annual Meeting> -2
Low Impact Special Trackwork for Heavy Haul Freight Operations Technologies Successfully Implemented: Flange Bearing Frogs Diamond Crossings Turnout Frogs Improved Switch Geometries Low Entry Angle Switches for HAL Frog Running Surface Profiles Conformal Profiles Ramps for High Angle Frogs Curved Entry Guard Rails Foundations for Frogs 2009 TRB Annual Meeting> -3
Load Environment Vertical loads on high angle diamond crossing at FAST (315 K hopper) 2009 TRB Annual Meeting> -4
Vehicle Performance on Diamond Crossings Pictures of damage to diamonds 2009 TRB Annual Meeting> -5
Diamond Crossings Track Transition Problems Background: Car parts graveyard around diamond 2009 TRB Annual Meeting> -6
Types of Crossing Diamonds Conventional Tread Bearing Frog Unsupported flangeway gaps Wheel is tread bearing throughout Advantages: Lower first cost Allowed by FRA Track Safety standards Flange Bearing Frog Continuous wheel support Wheel transitions from tread to flange bearing Advantages: Lower dynamic loads 2009 TRB Annual Meeting> -7
Types of Crossing Diamonds Flange Bearing Frog 2009 TRB Annual Meeting> -8
Crossing Diamond Dynamic Loads Potential to Reduce Dynamic Loads Measured performance Conventional diamonds Measured performance FBF test diamonds Class 4 Track 2778-B1b 2009 TRB Annual Meeting> -9
Flange Bearing Frogs First Full FBF Diamond Installed under Waiver CSX Shelby, OH 40 mph Wheel fleet and diamond performance monitored by TTCI 2009 TRB Annual Meeting> -10
Evaluation of Designs and Initial Performance of FB Turnout Frogs Application: Mainline turnouts with very little diverging traffic Set out tracks Benefits: Expected service life: RBM: 200 MGT FB Frog: 1,000 MGT? Mainline ride quality Continuous surface 2009 TRB Annual Meeting> -11
Turnout Geometry and Components Evaluation Best Practices Prototype(s) for FAST Joint-Less Frog New Helper Arrangement Double Spiral Geometry Thicker Switch Point Composite Material Rods 2009 TRB Annual Meeting> -12 Hollow Switch Ties
Turnout Performance Next Generation Turnout Key Findings: Design Features Recommended for Revenue Service Application Spiral, Tangential switch alignment With Thicker point Switch rods out of ballast Hollow Steel Ties Need a stiffer clip to reduce point roll Over-tie rods Improved vertical stability: lining & surfacing requirements reduced by 60% 2009 TRB Annual Meeting> -13
SRI 9A STW Super Turnout Next Generation Turnout Key Findings: Forces lower Lateral forces continue to be ~30% lower Vertical forces are 10% lower than RBM s 30 MAXIMUM LATERAL FORCE (KIPS) 25 20 15 10 5 0 2009 TRB Annual Meeting> -14 40 MGT 100+ AREMA STR AREMA CRV LOW ENTRY TANG, SPIRAL
SRI 9A STW Super Turnout Next Generation Turnout Key Findings: Service Life of Switch Points Thicker point and lower forces Longer average life than AREMA style 300 Switch Point Life FAST SERVICE LIFE (MGT) 250 200 150 100 50 0 AREMA STR AREMA CRV LOW ENTRY TANG, SPIRAL 2009 TRB Annual Meeting> -15
SRI 9A STW Super Turnout Next Generation Turnout Key Findings: Design Features Recommended for Revenue Service Application Low dynamic load frog Moveable point or wing frogs Fixed point Solid with improved running surface profiles 2009 TRB Annual Meeting> -16
Frog Profile Design Cross Section Profile P Designs High Stresses Relocated Corner Stress Distributed Stress Current profiles Point contact on flangeway corner 2009 TRB Annual Meeting> -17 Conventional prototype Flat running surface, larger corner radius Point contact away from flangeway corner Conformal prototype 1/20 taper running surface, larger corner radius Conformal contact away from flangeway corner
Frog Cross Section Profile Design Conformal Conventional 2009 TRB Annual Meeting> -18
High Performance Crossing Diamonds Ramped Flangeway Corners Background: Frog corners are deformed Castings made to desired shape AMS deforms rapidly to undesired shape Effective flangeway gap goes from ~2 to 3-4 3 Dynamic forces increase significantly Ramp designed to: Provide for initial deformation Lift wheel over gap 2009 TRB Annual Meeting> -19
Running Surface Ramping for High Angle Frogs WHEEL LOAD DYNAMIC AUGMENT 3.5 3 2.5 2 1.5 1 20 40 60 80 100 120 SPEED (KPH) PREDICTED w/ramp PREDICTED wo/ramp MEASURED XING wo/ramp MEASURED w/ramp 2009 TRB Annual Meeting> -20
Guard Rail Entry Analysis Dynamic simulation modeling - curved entry will: Lower maximum forces Control wheel path better Circular entry contacts wheel sooner Provides smoother transition instead of abrupt impact Conventional Entry 14,000 12,000 10,000 8,000 Circular Entry Lateral loads (lbs) 6,000 4,000 2,000 6ftconvex 6ft standard 0-2,000 2009 TRB Annual Meeting> -21-4,000 0 2 4 6 8 10 12 14 16 18 20 22 24 26 Distance from end of guardrail (ft)
Load Environment of the Crossing Diamond Two types of impact loads seen at diamond crossings Higher frequency load due to wheel impacts. Contribute to broken components Lower frequency loading due to wheel bounce. Contributes to: ballast and subgrade breakdown tie deterioration surface and alignment problems 2009 TRB Annual Meeting> -22
NUCARS Study Optimal track damping is above measured Current Damping 2009 TRB Annual Meeting> -23
Diamond Crossing Foundation Design Attenuate Impacts (platework) Ballast designed to reduce settlement Attenuate Impacts (subgrade) Reduce Settlement 2009 TRB Annual Meeting> -24
Development of Low Impact Special Trackwork Implementation: Flange Bearing Frogs are successful Full FB diamonds being implemented under waiver OWLS diamonds being widely implemented FB turnout frogs in revenue service tests Premium turnout components becoming standard for HAL lines Ramped running surface diamonds are industry standard Curved Entry Guard Rails are being adopted as Industry Standard Optimally damped foundations in test by industry 2009 TRB Annual Meeting> - 25