Two years ago, King County Metro made the decision to replace its aging fleet of electric trolley buses with…new electric trolley buses. (The transit agency had also looked at getting rid of wires entirely, and using diesel and diesel hybrid buses.) This week, Metro announced they’ve teamed up with the San Francisco Municipal Transportation Authority (SFMTA) on a contract to buy the trolley buses from Winnipeg-based New Flyer. (It’s Metro’s contract with New Flyer; SFMTA will be able to buy some of the buses Metro orders.)

Metro plans to replace “up to 141 trolley buses” in 2015, says Rochelle UP, using a combination of federal and agency capital funds. (Metro’s projected service cuts are due to shortfalls in operational funding.) The agency currently runs a fleet of 159. Though the capital and operational budgets are separate, she noted that potential service cuts could factor into Metro’s order; at a given point, less bus service means fewer buses.

New Flyer may not be a name you’re familiar with, but you can ride New Flyer buses in Vancouver, Seattle, Portland, and San Francisco. Though based in Canada, the company also has manufacturing plants in Crookston and St. Cloud, Minnesota. Metro has been snapping up their diesel and hybrid low-floor models, in 40- and 60-foot lengths, for most of the 2000s.

San Francisco, which has the largest trolley bus fleet, has also caught low-floor fever. The low floor (just 10 inches high when the bus is “kneeling”) removes the need for stairs — or complicated lifts for wheelchairs. As you’ve likely seen on the diesel/hybrid low-floor models, a mechanical “gangplank” extends lets people with wheelchairs and walkers roll themselves right on.

Electric-only buses, of course, have the advantage over diesel-engined, or even hybrid, buses when it comes to environmental impact. Their sole demerit is the visual clutter provided by the aerial wires that serve up the electricity. And on the West Coast, hydroelectric plants keep that electricity reasonably cheap and plentiful, year-round. (San Francisco’s fleet is powered by Hetch Hetchy. Seattle City Light’s fuel mix is more than 92 percent hydroelectricity.)

Plus, the electric motors generate higher torque at low speeds, compared to diesels — on steep hills, trolley buses accelerate from a standstill while diesels stay geared down to pull their weight.

Metro’s 60-foot Breda buses (purchased in 1990 and converted to electric-only in the mid-2000s) have just two doors are showing their miles, while their 40-foot Gillig buses use propulsion systems from 1979. The 60-foot models from New Flyer will have three doors, to speed entry and exit. All boast regenerative braking (contributing to a 30-percent reduction in power usage compared to existing trolley buses) and the ability to travel “off-wire” for short distances, to get around road construction, downed lines, parades and marches — the host of things that can currently leave trolley buses stacked up. [UPDATE: Ogershok says New Flyer promises an off-wire distance of two and a half miles, powered by onboard batteries.]

It’s early on, so Ogershok couldn’t speak to much about the finished look-and-feel of the new coaches, but she did confirm that all would come with air-conditioning, and will able to “kneel” their full length, not just at the front door, as is currently the case.