New York City's High Line, a public park built atop a disused elevated railway along the Manhattan's west side, is something that would make a damn fine addition to any urban centre. The problem is, of course, that not every city has an old elevated railway with which to work. And then there's the problem of civic will. The High Line remains the product of a tireless campaign on the part of community members to adapt and reuse a structure that was destined to be demolished many times over.

In Toronto there has been more than one proposal to turn the Gardiner Expressway into a similar type of public greenspace, but the likelihood of converting an active highway into a park is, you'll forgive me, anything but realistic in a city that's struggled to show vision on projects of this nature (let's get the West Toronto Railpath extended downtown, and then we can talk, ok?).

That said, there are other urban elements in this city — hiding in plain view, as it were — that could be converted into valuable public space. The Railpath is a good example of this, but so to is the so-called Green Line, a meandering five kilometre hydro corridor that stretches between Lansdowne and Davenport to around Spadina and Dupont. While lacking the intrigue of an elevated railway, much could be done to make this a marquee addition to our portfolio of parkland.

And a newly launched design competition is looking to do just that. The Green Line Ideas Competition asks "architects, landscape architects, designers, planners, artists and community members" to "propose how a piece of infrastructure can be transformed into exemplary public space."

Many elements along the five kilometre route are already used as parks — both officially and otherwise — but the competition would like to showcase novel ideas for ways to create a continuous corridor. Alas, this is the earliest stage of the transformation process, and the winning design isn't destined to be built. The City of Toronto is missing key parts of land to complete the link, but according to a press release, local councillors are already negotiating for licences to the missing pieces.

And, really, if comparisons to the High Line are warranted it'd be good to remember just how long it took to get that project realized. This ideas competition will culminate in a community event in the spring, which should serve to get discussion and momentum going for a full-scale push to bring the Green Line into reality.

Lead image Derek Flack / Map courtesy of the Green Line Ideas Competition