RSAC Engineering Task Force Results
PRIIA 305
Technical Sub Committee
April 22, 2010
Chicago, Illinois
Robert Lauby & Eloy Martinez
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Crashworthiness Goals
• Preserve Occupant Volume
– Maintain Safe Space; Minimize Local Compartment Penetration;
and Ensure Occupant Containment
• Limit Forces and Decelerations to Survivable Levels
– Limit Deceleration of Occupant Volume; Restrict Secondary
Impact Forces; and Maintain Secure Interior Fittings
• Note: Survivability Depends on Many Factors – Goal is to Preserve
Volume and Limit Forces for Moderate and Low Speed Collisions
2
Need for RSAC ETF:
Clarity Needed on Waiver Process
• Issue: current standards present difficulties in application towards
new designs that implement Crash Energy Management or built to
alternative standards
• Industry is approaching FRA with waiver requests:
– Caltrain Commuter Rail, CA
– California High Speed Rail, CA
– Desert Express, NV
– Capital Metro Transit Austin, TX
– Denton County Transportation Authority, TX
– Dallas Area Rapid Transit, TX
– Others…
• Some perceive waivers as high risk and inefficient processes with
potentially inconsistent review
Everyone wants an exception!
3
Other Issues
• Carbuilders looking for additional guidance before making major
investments
• Operating authorities looking for new car procurements to replace older
fleets for:
– Increased efficiency (weight savings) versus other designs
– Compatibility when mixing different equipment types on same corridor
– New operational requirements – ADA, low floors, etc…
• Both passenger rail operators and carbuilders need additional guidance
(early in the procurement process) to eliminate the risk of ordering
equipment that will not be waived and/or accepted by FRA.
4
Desired Metrics of Success
• Preservation of occupied space
– For collision scenarios preserve space up to a
minimum safe closing speed
– Apply traditional load requirements for other aspects
of car designs (e.g. side and roof loading, etc)
– For both cases maintain occupant containment
• Maintain survivable environment within interior
of cars
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RSAC Engineering Task Force
• Mission Statement:
– Produce a clear set of technical evaluation
criteria and procedures to provide means of
comparing crashworthiness performance of new
trainset designs with compliant Tier I equipment
– Technical evaluation criteria defined for: overall
train, individual car, and interior level
performance
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Scope
• Structural crashworthiness
– At train and individual car levels
• Preserve occupied volume
• Limit secondary impact environment
• Occupant Protection
– Compartmentalize Occupants
– Limit Forces Imparted to Occupants
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Approach
• Performance Criteria for Prescribed Impact
Scenarios
– e.g., Train-to-train Collision, Grade-crossing Collision,
etc.
– Assess Crashworthiness Performance with Tests and
Computer Simulations
• Design Criteria for Fundamental Features
– e.g., Occupant Volume Integrity
– Verify Fundamental Aspects with Nondestructive Tests
and Manual Calculations
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Summary of
Train-level Criteria
CFR
238.203
238.219
Concern
Load Case
Collision with Alternatively-designed train
conventional collision with conventional
equipment
locomotive-led train
(a)20 mph, cab car led
Truck
(b)25 mph, locomotive led
attachment
DRAFT
Pass/Fail Criteria
Preserve occupant volumes
Trucks remains attached
238.205
Colliding car
override
Alternatively-designed equipment
Underframes remain engaged
collision with conventional
Minimize wheel lift
locomotive, (a) aligned and (b) with
3 inch vertical/3 inch lateral offsets
238.207
Connected
equipment
override
Alternatively-designed equipment
Underframes remain engaged
collision with conventional
Minimize wheel lift
locomotive, (a) aligned and with 2
inch vertical/2 inch lateral offsets of
first car-to-car connection
Summary of
Car-level Criteria
CFR
Concern
Load Case
DRAFT
Pass/Fail Criteria
238.203
Occupant
volume
integrity
(a) 800 kips, or
(b) 1000 kips, or
(c) 1200 kips on design load path
(a) No perm. def.
(b) Limited perm. def.
(c) Without crippling
238.209
Fluid entry
Based on design review
(a) Equiv. to ½” 25 ksi steel
(b) Inhibits entry of fluids
(c) Affixed to structure
238.211
and 213
End structure
integrity of
cab end
(a) Absorb135 ft-kip of energy for
impact offset 19 inches from centerline
(b) Absorb 120 ft-kip of energy for
impact aligned with sidewall
No more than 10 inches of
longitudinal, permanent
deformation
238.213
Non-cab end
corner post
(a) 150 kips at floor height
(b) 30 kips 18 inches above floor
(c) 20 kips at ceiling height
(a) Without failure
(b) Without perm. def.
(c) Without failure
238.215
Roof integrity
Car upside down, supported by roof
(a) No occ. vol. intrusion
(b) ½ yield or buckling
238.217
Side structure
integrity
Design requirements on sidewall
stiffness and material properties
Vert. modulus (in3) > 0.3 x L
Hor. modulus (in3) > 0.2 x L
DRAFT
Summary of
Interior Criteria
CFR
Concern
Load Case
Criteria
238.233
Interior
fixture
attachment
Fixtures: 8/4/4 Longitudinal/
lateral/ vertical quasi-static load
Seats: 8 G longitudinal dynamic
pulse
Fixtures and seats remain
attached
(APTA)
Occupant
protection
features
8 G longitudinal dynamic pulse
Injury criteria within accepted
limits
Note: Existing Glazing Standards, 49 CFR 223 Safety Glazing Standards –
Locomotives, Passenger Cars and Cabooses, also to be applied to alternatively
designed passenger equipment.
Scope of ETF Guidelines
ETF Guidelines:
• Applies only to trainsets.
• Identifies performance considered
equivalent to conventional designs.
• Allows qualifying equipment to operate
under a waiver.
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SCRRA Procurement Process
Purpose was to add Crash Energy
Management to a conventional FRA
compliant rail car.
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Ad Hoc CEM Working Group
• Ad Hoc Committee Formed to Develop CEM
Procurement Specification for SCRRA
Over 4 Months
– Technology Transfer Symposium held to present
technical basis for inclusion of CEM
– 1st Meeting: developed consensus on energy
absorption levels and discussion of scenarios
– 2nd Meeting: consensus reached on scenarios and
discussion of evaluation procedures
– 3rd Meeting: consensus reached on evaluation
procedures and discussion on evaluation criteria
– 4th Meeting: consensus reached on criteria and
discussions held on existing standards
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CEM Procurement Specification
• SCRRA Released Specification on September
16, 2005
• Train Level Performance – survive series of
collision scenarios (no intrusion into occupied
space and limit SIVs)
• Car Level Performance – crush zones on cab
and non-cab ends to absorb 3.0 and 2.0
million ft-lbs of energy respectively
• Component Level Performance – manage
kinematics at coupled and colliding interfaces
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Crash Energy Management
Structural Features
Cab End
Non Cab End/Trailer Car
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Structural Testing
F-End Underframe Absorber, LTM
PEAM, Frangible Element and
Sliding Sill
B/R-End Underframe Absorbers,
Upper Absorbers, Roof Absorbers
and Sliding Sill
F-End Loading at coupler 800kips
B/R-End Loading at coupler 800kips
Component Testing –
Energy Absorbers
Pre-test
Pre-test
Post-test Deformation State
Post-test Deformation State
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Component Testing –
Interior Occupant Protection
Pre-Test
8g Sled
Post-Test
8g Sled
Energy Absorbing Tables
Energy Absorbing Seats
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SCRRA Applied CEM
• New Cab Cars and Trailer Cars with CEM
structure and Components
• New Interior Equipment based on CEM
technology
• Applying CEM research to optimize train
configuration
• Modification of existing fleet with CEM
components and techniques
* Taken from “Practical Application to Passenger Equipment” at APTA Rail Conference
June 17, 2009 in Chicago, IL
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Conclusion*
• The passenger rail industry now has the opportunity to
adopt advances in crashworthiness that improve the
safety of the traveling public in collisions and
derailments.
• The advances have been successfully tested and have
been shown to be practical for production.
• Industry should plan to update the CEM design
standard for consistent application of the advances
using designs that have been verified to provide
improved crashworthiness performance.
* Taken from “Practical Application to Passenger Equipment” at APTA Rail Conference
June 17, 2009 in Chicago, IL
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Conclusion
• Application of work from RSAC Engineering Task Force
applicable to comparison of trainset designs
• Current PRIIA 305 mandate specific to equipment
classes – e.g. bi-level coach, single level coach, etc..
• Addressing individual car design specification better
modeled after CEM procurement specification
developed by Ad Hoc Working Group
• CEM designs lend themselves to use of standardized
components attached in a modular fashion
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Questions?
Robert Lauby
Eloy Martinez
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