In about five years, Toronto will unveil the largest expansion of the TTC's rapid transit network since the 1960s. The Crosstown LRT will consist of 25 stops stretching across 19 kilometres of Eglinton Avenue, 10 of which will be underground.

While this massive project won't open until 2021 (assuming it stays on target), it's already transforming Toronto in profound ways.

The construction of rapid transit spurs development, whether it's a heavy rail subway or an LRT, but the placement of a new line is always crucial. In the case of the Eglinton Crosstown, there are already plenty of signs that the route will lead to a huge increase in density along the street after which it's named.

It'd be overreaching to claim the condo boom in and around Yonge and Eglinton as the direct result of the coming LRT. The area is already so well served by transit thanks to its proximity to the Yonge Line.

When you follow the route away from the core, however, it's amazing to see how many developments have already been proposed, many of which will be completed shortly after the LRT opens.

As developers look for less expensive land outside of the city's core, the Crosstown represents an ideal scenario for future growth. Much of this will be concentrated on the east side of the line, as that's the corridor where huge sites of land are ripe for redevelopment.

When LRVs start running on the Crosstown, they will emerge from the underground portion of the line just east of Laird Avenue to pass through an Eglinton Avenue marked by tall towers and new mixed use communities in place of the mid-century shopping malls and other low density land uses.

At Leslie Street, there's the On the Park development in the works at the site of the former Four Seasons Inn on the Park. It'll have 1240 condo units spread over four towers ranging between 28 and 39 storeys. Throw in 943 square metres of commercial space, and you have a whole new community.

One stop further east, there's an even bigger redevelopment in the works on the former IBM/Celestica lands. This is a 60 acre site now controlled by a consortium of developers (Diamond Corp., Lifetime Developments, and Context Development Inc.).

We don't know exactly what this will look like when it's all said and done, but concept drawings show what you might characterize as a brand new neighbourhood here, complete with residential, retail, office space, parks and a community centre.

Continuing along in our brand new Flexity Freedom LRV, we pass by the Don Valley Parkway before arriving at the next redevelopment sites. The sea of parking lots that currently marks this area will be entirely transformed when both Eglinton Square shopping mall and the Golden Mile become vertically oriented mixed use communities.

The plans for Eglinton Square call for 1,640 residential units spread over five buildings ranging from 25 to 40 storeys. There will also be a major retail component preserving the current use of the site as it's diversified and intensified.

The Golden Mile, on the other hand, is even bigger. A whopping 2,500 residential units are proposed for 11 new buildings, again with a significant retail component at grade. The death of the mid-century shopping mall in Toronto will come at least partially at the hands of light rapid transit.

There are also intensification plans in the works at 1891 and 1966-2050 Eglinton East further to the east. And that's just the stuff in the works right now. Can you imagine how many more projects might be proposed over the next five years?

Planners often point out that the Bloor-Danforth subway line in Toronto never brought with it the type of intensification that you might expect of a major subway line. Part of the reason for this is that it services so many established low rise Toronto neighbourhoods and was built along a route already populated with two storey buildings.

This will not be the case along Eglinton Avenue, particularly in the east end, where the number redevelopment projects already in the works is positively dizzying.