Seattle is looking for ways to improve streetcar electrical systems to avoid repeating a March 1 incident where a train slid 2½ blocks on First Hill.
The momentary loss of power from a low-voltage battery was enough to send a Seattle streetcar skidding down Broadway on its rails for 2½ blocks, a safety hazard that technicians are still trying to cure several days later.
Though nobody was injured, the incident March 1 disabled four kinds of braking methods on the streetcar — and explains why city transportation chief Scott Kubly, citing an abundance of caution, is keeping the entire First Hill line closed.
It also raises a question about future safety on First Avenue — where in 2020 a new extension will send trains downhill as crowds of residents and visitors walk across First Avenue. Future trains may need to be re-engineered so they’re skidproof.
As of Friday, electrical tests were still being performed in the maintenance base, to be followed by on-street tests, said Andrew Glass Hastings, transit director for the Seattle Department of Transportation (SDOT).
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He wouldn’t offer a restart date, noting that permission must be given by King County, state and federal rail staff.
The city’s year-old Inekon cars, which push the frontier of technology by running partly off-wire, can be retrofitted soon, but to continue long-term they may need new components from overseas, city rail manager Mike James told City Council members this week.
City Councilmember Mike O’Brien, chairman of the Sustainability & Transportation Committee, guessed service might be a couple weeks away.
Final design is underway to build the $135 million downtown extension, called the Center City Connector, to open in 2020, linking the First Hill and South Lake Union lines.
By then, the entire fleet is expected to run off-wire downhill using stored battery power, a design innovation meant to avoid conflicts with King County Metro’s trolley-bus wires.
The March 1 incident happened at Boren and Broadway aboard the gold-colored streetcar when a circuit breaker tripped near a low-voltage battery. The internal battery power operates lights, gauges and brakes.
SDOT says the brakes automatically activated, in parking mode, as designed. The steel wheels locked as the train was going 20 mph.
The glitch disabled four other stopping methods: the streetcar’s regenerative braking, similar to that used on a hybrid car; the primary hydraulic disc brakes that operators use all day in frequent stops; the four track brakes, which sit between the wheels and can press downward on the rails; and sand an operator can dump to add friction during a sudden stop.
“One thing we’re looking at is, in the no-power mode, can those braking options be employed?” James, the rail manager, told council members this week.
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Inekon, the Czech company that built the streetcars, is collaborating to diagnose the problem, and its railcars remain under warranty, James said.
The company should be billed for replacement buses operating at peak times, and for lost train service, said City Councilmember Rob Johnson.
The First Hill route, which opened in January 2016, carries 3,000 to 3,500 riders a day, SDOT reports. Johnson says they serve a burgeoning market of commuters transferring from Sounder or light-rail trains.
Critics have long argued trolley buses would do the job far cheaper.
Riskier in old days
Seattle’s first streetcars in 1884 were known to run amok as horses pulled them down Pine Street and along the waterfront.
“Derailments there were almost daily occurrences as the horses, unable to check their momentum, careened at breakneck speed around the hairpin curve,” wrote historian Leslie Blanchard.
Streetcars are much safer nowadays.
However, in an abrupt stop, their steel wheels can develop flat spots from erosion, then skate on the rails, like a bicycle tire losing rubber tread.
This has happened in Portland, which has the nation’s longest modern streetcar network, especially if leaves or de-icing salts cover the rails.
“We’re talking about a couple of feet, not a major slide,” Dan Bower, executive director for Portland Streetcar. The network there includes a slope similar to Seattle’s First Hill, he said. Streetcars slow to 5 mph when crossing a flat pedestrian plaza near the Willamette River, where passengers can take the city’s aerial tram.
Portland streetcars aren’t susceptible to the same electromechanical problem, Bower said. The three original South Lake Union streetcars in Seattle continue to operate trouble-free, but newer trains were pulled in “an abundance of caution,” Kubly said.
“As far as we know, it’s an isolated issue on one of these vehicles,” rather than an endemic local or national risk, Glass Hastings said Friday.
When the downtown corridor is done, First Hill streetcars will continue every 10 minutes north into downtown, while the South Lake Union trains will go every 10 minutes past Westlake Station toward Pioneer Square — so they overlap every five minutes on First Avenue.
One safety factor is that First Avenue’s three busiest walking locations also will have train stops nearby, so streetcars ought to be approaching at less than the 20 mph cruising speed.
Across town, Sound Transit’s much faster light-rail trains have struck at least seven people walking near Rainier Valley median stations in the past seven years.
The downtown streetcar project has received a $75 million federal grant, along with $60 million in local funding. An estimated 20,000 people a day are projected to travel the full system.
O’Brien said the streetcar skid doesn’t make him concerned about pressing forward with downtown rail construction. The city is soliciting bids now, so it will have a choice of train builders.