Sound Transit has completed implementation and certification of Positive Train Control (PTC) on all Sounder commuter rail vehicles that run between Lakewood and Everett. Positive train control technology can control train movements under certain conditions, automatically applying brakes and avoiding collisions.

Under the Positive Train Control system, should an engineer exceed the permitted speed or fail to brake on approach to a work zone or a signal, PTC will automatically apply the brakes and stop the train.

Automated Positive Train Control system increases Sounder riders’ safety from Sound Transit on Vimeo.

There are three categories of PTC equipment: Wayside equipment which is installed on the track; onboard equipment which is installed on the train; and back office equipment which is installed in the train operations center. Once the system is operational wayside radio and global positioning systems (GPS) determine train location and ensures trains are operating within established parameters.

Sound Transit implemented PTC in close collaboration with Burlington Northern Santa Fe (BNSF), an industry leader in PTC and the operator of Sounder service under contract to Sound Transit. PTC equipment on trains and tracks must communicate seamlessly and routinely with the back office systems deployed by BNSF. Sound Transit PTC equipment is fully interoperable with BNSF systems. Sound Transit executed its contract for installing PTC equipment in 2013, well ahead of many passenger rail agencies, and completed the installation and commissioning last year well in advance of the federal government’s deadline.

Sounder trains from Everett to Seattle began testing PTC in June 2017. Sounder trains from Tacoma to Seattle began testing PTC in August 2017. Sounder also operates on tracks owned by the agency between Tacoma and Lakewood known as the Lakewood Subdivision. Sounder service is also certified to operate under PTC in this subdivision.