 Service was inaugurated on June 8 , 1999 , on a 2 @.@ 7 @-@ mile ( 4 @.@ 3 km ) route from Portway Street to 36th Street . The principal boarding location was at the Columbia River Maritime Museum ( at 17th Street and approximately the middle of the route ) , and initially there were no other set stops . Several designated stops were added later , and some of these include a bench and small shelter . Passengers are still permitted to flag @-@ down the trolley in between the posted stops . 
