On March 11, Sound Transit launched its wig wag train pilot. The pilot is being tested on the agency’s 1 Line train No. 12 train and features technology that is designed to improve train visibility and passenger safety along the at-grade portions of the agency’s light-rail network.
Sound Transit notes the technology in the wig wag train is already employed on Sounder locomotives and cab cars, as well as in select light-rail systems throughout the U.S. The pilot is part of the agency’s continuing efforts to improve passenger, pedestrian and motorist safety while interacting with trains in the Rainer Valley.
According to the agency, the wig wag train uses a pattern of flashing lights that are tied in with the train’s bell and horn systems that begin flashing when triggered by the operator. The flashing of the lights is designed to combine with the audible warning from the bells and horns to provide enhanced warnings in any areas where there are potential conflicts with a train.
Before entering pilot service, Sound Transit notes the wig wag program went through an extensive series of tests. While the lights themselves are the same as any other Link light rail vehicle (LRV), the agency says control and wiring elements needed to be updated and tested to tie together the system of lights, horns and bells that operators use to keep people safe.
According to the agency, the testing was followed by a series of live evaluations, where test trains traversed the 1 Line with observers on board and following in cars and on platforms to evaluate the lights and passenger reactions to them. The final test, which took place on March 10, featured a full four-car train, led in each direction by the two LRVs equipped with wig wag technology, traveling through the Rainer Valley four times.
The pilot project follows in the footsteps of several other light-rail operators, including Metro Transit in Minneapolis, which Sound Transit says that they found their pilot so successful that they’re retrofitting their entire fleet with the feature. Sound Transit says that during its pilot phase, the wig wag headlights will be evaluated by staff at Sound Transit and King County Metro to determine the path forward for the program.
Sound Transit notes the wig wag train got its name because “wig wag” refers to an old-fashioned railroad crossing indicator light, which was designed to swing back and forth to indicate a grade crossing. According to the agency, the swinging motion was said to be reminiscent of a dog wagging its tail.
