Train Detection Systems

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. Train Detection

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

5. Train Detection Considerations • Method of Train Operation • Maximum Speed of Trains • Mix of fast and slow trains • Frequency of switching moves 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) 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 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 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. 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 Train Detection

11. Enhancement in CWT 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 Train Detection

13. Display Interface Train Detection

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

15. New Design Tools- Office Configuration Editor 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 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) 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 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 Train Detection

20. Loop Detectors mitigate Shunting Issues Train Detection

21. Loop Detectors mitigate Shunting Issues Train Detection

22. Relative Cost of Sub-Systems AREMA 36-4 Study 2002 Train Detection

23. Thank You!Please Attend the RSSI Exhibition Train Detection