1. May 20, 2008 Train Detection 1 Train Detection Systems Mid-States Highway-Rail Grade Crossing Safety Conference Session 4 Use of New Technology for Highway-Rail Intersections John T. Sharkey, P.E. Safetran Systems Corp.

2. May 20, 2008 Train Detection 2 Standards MUTCD Part 8 - Standard Standard: Train detection circuits, insofar as practical, shall be designed on the fail-safe principle.

3. May 20, 2008 Train Detection 3 Regulations FRA Part 234 Sec. 234.227 Train detection apparatus. (a) Train detection apparatus shall be maintained to detect a train or railcar in any part of a train detection circuit, in accordance with the design of the warning system. (b) If the presence of sand, rust, dirt, grease, or other foreign matter is known to prevent effective shunting, a railroad shall take appropriate action under Sec. 234.105, ``Activation failure,'' to safeguard highway users.

4. May 20, 2008 Train Detection 4 Train Detection Considerations Detection Circuit Length dependent on –Maximum speed of train –Design warning time –Equipment reaction and buffer time –Clearance times –Advance Preemption Time

5. May 20, 2008 Train Detection 5 Train Detection Considerations Method of Train Operation –Maximum Speed of Trains –Mix of fast and slow trains –Frequency of switching moves

6. May 20, 2008 Train Detection 6 Train Detection Circuits Three types of fundamental operation rely on train shunting track –Discrete Track Circuits DC Track Circuits (1871) AC Track Circuits AC/DC Track Circuits Audio Frequency Overlay Track Circuits (1960’s) –Motion Sensing Systems (1960’s) –Constant Warning Time Systems (1960’s)

7. May 20, 2008 Train Detection 7 MS & CWT Systems Motion is sensed as a change in EZ Prediction (CWT) is a function of the Rate of Change in EZ

8. May 20, 2008 Train Detection 8 Motion Sensing Systems Advantages –Maybe appropriate on low density lines or where normal train moves are at the maximum speed –Cost effective, no special circuitry to detect stopped train –All active circuitry at crossing (not distributed along the track) Disadvantages –Longer or varying warning times –Wayside signals, etc, may cause the need for coupling insulated joints

9. May 20, 2008 Train Detection 9 Constant Warning Time Systems AREMA Definition: Constant Warning Time Device Current : A device used as a part of a highway-rail grade crossing warning system to provide a relatively uniform warning time. Proposed: A motion sensitive device capable of monitoring the speed of an approaching train and predicting the arrival of the train at the crossing to provide a relatively uniform warning time in accordance with a preset value.

10. May 20, 2008 Train Detection 10 Constant Warning Time Systems Advantages –Provides relatively uniform warning time, which improves credibility –Cost effective, no additional special circuitry to detect stopped train or varying speed trains –Ability to predict to downstream adjacent crossings (DAX) –Newer systems have many enhancements Disadvantages –Wayside signals, etc, may cause the need for coupling insulated joints –Wayside signals and interlockings may cause the need for additional units

11. May 20, 2008 Train Detection 11 Enhancement in CWT

12. May 20, 2008 Train Detection 12 Recent Enhancement in CWT Complete crossing system - “Crossing in a box” 6 Track system is the equivalent of having in one integrated product without all the interconnected wiring that contains the following: –Six CWT track circuits including Intelligent Islands and 9 Prediction Processes (Prime & 8 DAXes per track) –A 40Amp Crossing Controller –CPU Event Analyzer/Recorder and I/O Module –A field-programmable Vital Radio Links for Remote Prediction –Multiple Vital Timers and Vital AND Gates –Embedded PC Display Module for diagnostics and troubleshooting

13. May 20, 2008 Train Detection 13 Display Interface

14. May 20, 2008 Train Detection 14 Taking Tracks Out of Service Advanced options are available to take tracks or groups of tracks out of service to facilitate troubleshooting or track maintenance work

15. May 20, 2008 Train Detection 15 New Design Tools- Office Configuration Editor

16. May 20, 2008 Train Detection 16 Monitoring Philosophy The CWT reports its logic states to the Recorder for use in alarm calculations and event storage The Recorder monitors the actual I/O points on the back-plane of the CWT The Recorder receives information from the trackside equipment through its trackside sensor package

17. May 20, 2008 Train Detection 17 Monitoring Philosophy The Recorder knows what the CWT wants to do (LOGIC) The Recorder knows what the CWT tried to do (I/O POINTS) The Recorder knows what actually happened trackside (SENSORS)

18. May 20, 2008 Train Detection 18 Enhancements in Traffic Signal Preemption Preempt Health Input –Provides a “health check” of the interconnect relay in the RR house –Forces a false activation in the rare event of a false preemption due to an open interconnect circuit Traffic Signal Health Input –Provides a “health check” of the traffic system to the RR –Forces warning system into Simultaneous Preempt in the rare event that the traffic signals are in 4-way flash or dark

19. May 20, 2008 Train Detection 19 Enhancements in Traffic Signal Preemption Termination of Track Clearance –Advance Preempt Delay Timer Fixed time interval between Advance Preempt call and Warning Device Activation, so that slowing train will not cause Track Clearance green to end before Warning Devices activate –Gate Down Indication Second output from RR to indicate gate(s) in the direction of traffic towards the intersection is down allows Track Clearance green to end

20. May 20, 2008 Train Detection 20 Loop Detectors mitigate Shunting Issues

21. May 20, 2008 Train Detection 21 Loop Detectors mitigate Shunting Issues

22. May 20, 2008 Train Detection 22 Relative Cost of Sub-Systems AREMA 36-4 Study 2002

23. May 20, 2008 Train Detection 23 Thank You! Please Attend the RSSI Exhibition