When the first of the sleek new low floor, air-conditioned streetcars leave Spadina station this summer it will mark the beginning of the end for the 195 iconic red, white, and black streetcars currently circulating in Toronto. At nearly 40 years old, the CLRVs, as they are technically known, hark back to a time when the TTC seriously considered doing away with surface rail entirely.

The first six CLRVs - numbers 4000 through 4005 - are particularly special. Built in Switzerland, they still feature several interior design choices not found on other TTC streetcars. The very existence of the "original six," and the streetcars that followed, is the result of a well-timed and effective citizen-led protest.

The story starts in the early 1970s, when Toronto, like Montreal, Ottawa, Vancouver, and many other cities in North America, did not foresee a future for streetcars: Toronto's some 400 maroon and cream Presidents' Conference Committee vehicles were nearing retirement age and only a costly new fleet of streetcars could make future service viable, the TTC said.

By 1972 the official TTC plan was to gradually replace Toronto's streetcars with trolley buses - electric vehicles powered by overhead wires - or diesel vehicles, and it had already begun using the former on St. Clair east of Yonge in 1971. The rest of the line was due to be converted by the end of the year. The Dundas and College lines would be closed in 1975 and 1976; King and Queen cars would stop with the opening of the Queen Street subway line.

Enter Streetcars for Toronto, a citizens' committee organized to represent the users of surface rail. The group was founded by Andrew Riemiller, a University of Toronto psychology professor, with the intention of convincing the TTC that streetcars, popular with riders, made financial sense.

For a time, the province seriously considered replacing many of the old streetcar routes with a 56-mile monorail network. The magnetic levitation trains would have floated above a elevated concrete guideway, similar to parts of the Scarborough RT. Trouble was the West German Krauss-Maffei prototype displayed at the CNE in 1972 struggled to turn corners, which led the province to back away.

When it became clear the monorail idea was fundementally flawed, the province threw its weight behind a vehicle being developed by its own Urban Transportation Development Corporation, which would eventually become the ICTS Scarborough RT cars.

Meanwhile, a research paper by Streetcars for Toronto had successfully convinced the TTC that sticking with surface rail made financial sense. Since the Commission was 75 per cent funded by the province at the time, the vehicles it selected to replace the PCCs would also to be supplied by UTDC.

The design of the new streetcar was produced Swiss company SIG to the TTC's specifications. As part of the agreement with SIG, the first 10 vehicles would be built in Europe and shipped to Toronto where the design would be replicated by Kingston engineering firm Hawker Siddeley, the company that was also building Toronto's subway cars.

Of the initial 10 only six were completed - two were spliced together to make a prototype articulated model that would eventually lead to the ALRV streetcars that run on Queen. The rest were cancelled.

The six streetcars that made the Atlantic crossing were given the registration numbers 4000 though 4005 by the TTC and were different in several ways from many of the ones currently operating in Toronto.

Most noticeably, the front rows of seats were angled diagonally inward. The interior trim - ceiling air vents, seat backs, and panels that divided up the car - were accented bright red and the windows were sealed shut in anticipation of air conditioning. On the outside there were coupling devices that allowed the CLRVs to be joined together in a train.

The first of the $363,000 streetcars - about $2.1 million in today's money - were extensively thrashed during testing, leading to several derailments. One caught fire after a build up of snow caused an electrical short circuit.

According to Transit Toronto, a treasure trove of streetcar, bus, and subway information, the TTC ditched the angled seat arrangement shortly after the first six vehicles entered service on the now-defunct 507 Long Branch line, but the red interior trim remained. The subsequent 190 Canadian-built streetcars were given metal seats and a distinct 1970s wood-effect look.

What's most impressive about streetcars 4000-4005 (and really the rest of the fleet) is their longevity. All but one remains in service thanks to a team of mechanics at the TTC's Hillcrest facility - there's even an in-house blacksmith who forges metal parts.

The only streetcar to be destroyed, 4063, was gutted in anticipation of a refit program that was subsequently cancelled. The shell was sold for $4.32 in 2009.

When the first of the new low floor streetcars enters service on Spadina this summer the TTC will start the process of retiring the existing fleet, including the original six cars, on a "one-for-one" basis. The head of streetcar maintenance, Kevin Seto, says the ALRVs will be the first to go.

"CLRVs will be prioritized for retirement based on a number of different factors and just because these were the first vehicles built doesn't necessarily mean that they will be first to be retired," he says.

Finding one of the streetcars for an early farewell ride is tough: the TTC doesn't say where they are at any given time, though recently number 4000 has been on the 506 Carlton route between Main Street station and the High Park Loop.

Catch them while you can.

Chris Bateman is a staff writer at blogTO. Follow him on Twitter at @chrisbateman.

Images: Chris Bateman/blogTO, City of Toronto Archives