HIGHWAY RAIL GRADE CROSSING 4 QUAD GATES William H. Watson Amtrak Union Station 100 Gaspee Street Providence, RI 02903-1133 (617) 345-7518 (6170 345 7820 FAX watsonw@amtrak.com
ABSTRACT Design, installation and impact of Highway/Rail Grade Crossings with 4 Quad Gates The impact of the installation of 4 quadrant gates on Highway/Rail grade Crossings has caused much concern over the last couple of years. It has been the topic of discussion through out the country. Amtrak was required to install a test location as a condition for High Speed Rail. The Federal Railroad Administration ordered the closing, grade separation or full barrier protection for the thirteen crossing along Amtrak s shoreline route, between New Haven and Boston. Since there were no previous requirements or recommended practices existed, Amtrak started from the beginning designing a 4 quad crossing with vehicle presence detection. This paper presents our trial and endeavors to complete the task. We know that not all will agree with the way Amtrak reached their gold, but suggest that most of the stumbling blocks have been removed.
This paper will discuss the installation of 4 quadrant gates on Amtrak s main line in and around Mystic, Connecticut. In the early 1990 s, a decision was made to electrify the railroad, between New Haven, Connecticut and Boston, Massachusetts. The Federal Railroad Administration, in their approval of high-speed Rail Passenger Service Improvement Program, mandated that trains will not exceed 80mph over a crossing unless the crossing provides full barrier protection. Where speed is in excess of 95 mph, highway/rail grade crossing must be closed or have grade separation. There were thirteen grade crossings on the railroad between New Haven and Boston. To maintain the proposed schedule, a decision was made to build an overpass or close the majority of these grade crossings. This was not favorable with the local residents and state officials. At this time, local officials approached the FRA requesting assistance in developing an alternative to the building of an overpass or closure of their highway/rail grade crossing. Of the remaining highway/rail grade crossings, seven of these crossings, including School Street, provide the only access to the villages beyond the tracks. The FRA was already looking at various barricade systems in other countries. The 4- quadrant gate system was selected as best. They were looking for a place to test such an installation, for reliability and public acceptance. The estimate cost of the project was to be $1,000,000. The FRA funding assistance was 80%, and the state of Connecticut s share was 20%. The location selected was School Street in Mystic Connecticut on Amtrak s New Haven to Boston main line.
At the present time there are no guidelines, recommended practices or standards available for the installation of 4-quadrant highway/rail gate system. A variety of systems are being installed through out the country, with no two installations alike. As we speak, the highway/rail grade crossing committee of both American Railway Engineering and Maintenance of Way Association and the National Committee on Uniform Traffic Control Devices are working to write recommended practices for 4-quadrant gates at highway/rail grade crossings. Decisions that Amtrak had to make during the design of a 4-quadrant gate system was, but not limited to: 1. Should the exit gates fail up? 2. Should vehicle presence detector loops (VPDL) be used? Need or not needed? Vital or redundant? 3. Should exit gate decent be delayed from start of entrance gates? How long of a delay? Start when entrance gates are full horizontal? 4. Should traffic patterns be considered (i.e. school buses, semi-trucks, emergency vehicles, long low boat trailers)? 5. When should exit lights (pole & gates) start and stop flashing? 6. Should exit lights flash when being delayed? 7. How long should exit gates be horizontal prior to arrival of a train? 8. If exit gates does not go full down, does the gate need to be lifted? 9. If entrance gates fail to be full horizontal position, should the exit gates be held up?
10. Median barriers vs. traffic island vs. traffic separators? Need or not? 11. Roadway geometry as a factor? The first and most important decision to be made by Amtrak, was the selection of a vehicle presence detection system that would meet the railroad s requirement of failsafe. Many systems were tested, but none could meet the criteria. It was felt that a certain loop system manufactured by Reno A&E could be modified to meet the fail-safe provision. By installation of a test loop before the installation of the active loop, a reliable vehicle presence detection system was incorporated in the crossing circuits. A microprocessor-based system is used to check the loops, by observing vehicle operation of the active loops or by closing (or shorting) the test loops. This causes the loops to indicate as if a vehicle was detected and allows the loops to become a vital part of the system. This reliability allows us to give limited control of the exit gates and railroad signal system, to the vehicle presence detector loops. The operation of the highway/rail grade crossing is programmed similar to an interlocking, interfacing the tracks and the roadway. The east and west approach and island track circuit on each track and the three vehicle presence detector loops on each lane of highway are all interlocked together. In other words, the first to the crossing will have control of the crossing. This may sound like cars will be stopping trains, but in the two plus years of operation, we have stopped only one train due to a vehicle on the tracks. At that time a car had nosed under an exit gate, causing the cab signal to be taken away from the train. At 60mph, the warning time at School Street highway/rail grade crossing is approximately 50 seconds, and with the full barrier system, the
traveling public does not seem to mind the additional warning time before the arrival of a train. Full barrier gates take away the option of going around down gates. This removes the frustration of deciding to go or wait for the oncoming train. Amtrak is unique in the fact that its incorporates a continuous cab signal system on their tracks. Only approximately 9% of railroads in the United States have a cab system installed on its tracks. This was a major factor when designing the school street 4- quadrant gate system. The design used at School Street could be used as a typical application at any other highway/rail grade crossing without the cab signal feature. Our design of the 4-quadrant system is that the exit gates fail up. The entrance & exit gates descend and ascend together, and all lights at the crossing start to flash at the same time. All crossing signals are light emitting diodes (led) in 12-inch roundels. With the use of vehicle presence detector loops (VPDL), the need to delay exit gate descent is not required. A vehicle going over the crossing after the warning devices are actuated causes the exit gate in front of the vehicle to return or remain in a vertical position. The loops then have controlled the exit gate until they reach a full horizontal position. Activation of the any loop will cut out the train cab signal system. When a train steps on the approach to the crossing and the vehicle loop(s) shows occupied, the cab signal slowly degrades, causing the train to make a safety stop before occupying the crossing. When the vehicle clears the crossing, the cab signal is restored allowing the train to resume its authorized speed. Once all gates reach the horizontal position, actuation of the vehicle detector
loops will no longer have an effect on the gates, but will continue to reduce the train cab signals. A highway-crossing monitor and recorder are installed at the crossing to constantly verify the operation and the health of the system. An automatic dialing system notifies our maintenance dispatch center in Boston, along with local maintenance personal, of failures. The FRA monitors this highway/rail crossing through a closed circuit camera system, from the Volpe center in Cambridge, MA. When an approach is occupied, a picture is sent every 3 seconds to their center. Committee 36 is currently writing a recommended practice for the installation of 4- quadrant gate systems. There has been much discussion within the committee and with the FRA as to how the system should work. There is a flow chart from manual part 3.1.5 (recommended guidelines for the application of highway/rail grade crossing warning devices) that we call the decision tree. It is intended as a guide to improve and upgrade warning devices at highway/rail grade crossings. It is our intention that diagnostic teams will use this decision tree when reviewing a highway/rail grade crossing warning system. Manual part 3.2.15 recommends the design criteria for operating mechanism for both entrance gates that fail down and exit gates that fail up. Committee 36 is working on recommended design criteria for the installation of vehicle presence detector loops. Amtrak is installing seven more 4-quadrant highway/rail grade crossings in the same area as School Street. Our special concern is that seven of these crossings, including School Street, provide the only access to the villages beyond the tracks. We are
currently working on a way for the dispatcher to raise the gates in the event of a failure if an emergency occurs before maintenance personal can arrive. This concludes the installation of the 4-quadrant gate systems on Amtrak.