Not to play Mr Crabby, but it's a cable car. When I saw "street car," I thought of a trolley, the kind that is powered by electric motors that draw their power from overhead wires. San Francisco has an incredible collection of vintage trolleys and PCC cars that run along the Embarcadero. But the city also has cable cars, which are unique to SF. They're unpowered and are pulled along by cables that run under the streets. The motorman pulls on one of those levers (the other one is the brake), which allows a thingy underneath to grab onto the cable.
Other than that, nice looking project!