Sound Transit to use PTC on all Sounder trips by December

Sounder South at Safeco Field. Credit: Andy Tucker

Sound Transit will implement positive train control (PTC) on all Sounder trips by the end of 2018, according to Sound Transit Director of Systems Engineering Peter Brown.

In a presentation to the Sound Transit board on Thursday, Brown summarized the progress of PTC implementation. In 2008, the federal government mandated that all commuter rail systems implement PTC on all trips by 2020, and show progress on implementation by the end of 2018. Sound Transit expects to beat the deadline by two years.

PTC is an automated safety system that can apply a train's brakes during emergencies when an engineer has failed to do so. PTC can prevent dangerous events like the fatal Cascades derailment in DuPont at the end of 2017.

Sound Transit had some PTC systems installed on certain Sounder runs as early as 2016, but capital projects in Pierce County, including the Tacoma trestle and Point Defiance Bypass, delayed full implementation.

According to Brown, Sound Transit is currently commissioning PTC on new Bombardier cars that were delivered in 2018; those cars will enter revenue service in August. Systems testing and debugging is currently underway with older vehicles. Sound Transit is also working with WSDOT and Amtrak to make all passenger vehicles that run on the BNSF track interoperable with the PTC system.

"When the trains are configured and ready to go, the engineer goes through an initialization process which essentially establishes communications between the vehicle and the dispatching office. We measure the success with which that occurs" we're consistently in the 90 percent range, for a few months now," said Brown. "We are working to get that to as close as 100 percent as we can."

Brown said that, when errors do occur, they are due to faulty GPS antennas or a bug in the PTC software. The antennas were shipped defective. The system's contractor, Wabtec, will replace the antennas at their own expense. The software error, which causes a false positive and triggers braking, is not unique to Sound Transit; all other railroads that use Wabtec PTC also have the problem. Wabtec will release a new build of PTC that will address the error in early August.

Brown expects that performance will continue to improve as Sound Transit gains experience operating the equipment, and other operators finish their own implementation processes.

"PTC is a complex system in the early stages of deployment, and we expect reliability will improve with time," Brown said.

Meanwhile, WSDOT announced this week that they are targeting completion of the PTC work - and therefore a return of Cascades trains to the Point Defiance Bypass - this fall, a little ahead of the Federal deadline. System tests along the bypass, and crew training, are underway this summer.