Issues with Event Recorder Technology for Railway Accident Reconstruction

1
Issues with Event Recorder Technology for Railway
Accident Reconstruction

• Presented by
• Gary P. Wolf
• Rail Sciences Inc.
• Atlanta GA
• www.railsciences.com

2
Rail Sciences Inc.

• Independent Investigator of Railway Derailments
  and Accidents
• Have Investigated over 1000 Incidents using Event
  Recorders
• Have used all technologies from Paper Tapes, to
  Mag Tapes, to Solid State
• Have own playback facility and electronic scopes
  to diagnose problems

3
Evolution of Technology
4
Problems with Paper Tapes

• Mechanical Failures
• Inaccurate
• Affected by Locomotive Motions
• Only Speed
• No Mileposts

5
Problems with Mag Tapes

• Electro-Mechanical Failures
• Tape head Dirty
• Tape broken/ jammed up
• Tape not turning
• Affected by Heat Magnetic Fields
• Delay on digital Channels

6
Lead Locomotive
7
Lead Locomotive
Trail Locomotive
8
No Speed
9
?
10
42 MPH
11
42 MPH
40 MPH
12
Tie Breaker
42 MPH
40 MPH
13
Critical Data Channels

• Time
• Speed and Distance
• Throttle Dynamic Brake
• Amperage (Power Dynamic)
• Direction
• Air Brakes
• Automatic
• Independent

14
Uses of Event Recorders

• Determine status of longitudinal in-train forces
  at time of derailment
• Determine train deceleration rates
• Determine train stop distance
• Verify proper train handling
• Verify train speed
• Verify how many locomotives on-line
• Determine possibility of slack action

15
Head End
16
Head End
Rear End
17
(No Transcript)
18
Speed
19
Issues with Horn Channel

• How Actuated
• Electric Solenoid
• Air Pressure Switch
• Lag Time on Magnetic Tapes
• Soft Blow?
• Lead Unit only locomotive with pickup
• Do we need to record sound (decibels)?
• Current Technology not reliable

20
Digital Sampling Rates

• 6-12 delay with magnetic tapes
• Problem eliminated with solid state sample rates
  less than 1 second
• Can cause much confusion on mag tapes

21
Most Critical Issues

• Current number of data channels sufficient for
  99 of train accidents
• Greatest need is for more reliability
• Inspection Intervals
• How tested at shops
• Air Brake and Speed channel most prone to
  problems
• Adding more channels likely to decrease
  reliability

22
Most Critical Issues Cont

• Crashworthiness Issues
• Fire
• Water
• Impact
• Human Interface
• Lost, Damaged disks/tapes
• Chain of Custody
• Calibration
• Securing all locomotive recorders

23
Most Critical Issues Cont

• Interoperability
• Each system proprietary
• Quantum, Pulse, Qtron, TMACS, Bach Simpson, GE,
  Rockwell,Others
• Standard interface data format would facilitate
  obtaining data in field placing it in hands of
  investigators
• Accuracy of present system acceptable for most,
  if not all, reconstructions

24
Final Recommendation

• Pre-occupation with expanding the number of
  transducers and channels will only serve to
  dilute the basic functionality of the event
  recorder
• Put energy into improving system reliability and
  crashworthiness of the basic recorder
• Work towards Interoperability