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As discussed in my previous article on Toronto’s regional rail network within the City of Toronto proper, the Davenport Diamond Grade Separation is a project which seeks to eliminate one of the last major rail conflict points on the core network of Metrolinx-owned tracks with a substantial flyover on the GO Barrie line through Toronto’s Davenport neighbourhood. I was onsite with Metrolinx this past week to take things in on the ground and see the progress on this impressive project.
As many UrbanToronto readers will undoubtedly be familiar, the hourly bidirectional train service Metrolinx brought in a few years ago is still operating while the new grade separation and rail alignment is constructed. In order to safely coordinate work on the site, which stretches over a kilometre in length, site supervisors are talking to trains and rail traffic controllers to make sure workers are clear whenever a train passes through. The track that trains are currently operating on was actually the very first thing built for the project, diverting traffic from the original alignment which was centred in the right of way.
We entered the site at Paton Road, which is the location of a former pedestrian underpass. A new underpass is being constructed at ground level, as the trains will already be elevated at this point, and this will be accessible to all thanks to the lack of stairs. Some of the abutments which will carry the southern portion of the grade separation are already visible.
If you haven’t been following the project closely, both the northern and southern extents of the elevated portion will be built on MSE (mechanically stabilized earth). This is basically an embankment which is made narrow by integrating retaining walls. Instead of running a large embankment style wall through the whole area with bridges at the major crossings, Metrolinx did something more elegant and opted for a guideway for the central section. This isn’t unlike those you’d see on a modern elevated rail system like the Montreal REM or the Vancouver SkyTrain. That said, the guideway is on a substantially larger scale to be able to carry massive GO trains.
The starting point for the guideway are giant rebar forms, which are then encircled with forms that are used to create pillars of uniform profile but varying heights. There is also an intermediate step which involves using external heaters to warm the curing concrete. This helps keep the temperature optimal so that the concrete cures properly, improving strength and resiliency.
Of course, plans also call for this space to be turned into a pleasant public space with an integrated greenway in the future. The space freed up by elevating the guideway on pillars is significant and so this greenway could easily be more substantial than similar projects such as the West Toronto Railpath. One location that will be particularly interesting is at Dupont Street, where the sidewalks on the south side of the street will be turned into ramps connecting the street with the former surface level rail corridor as it passes overhead.
Now in order to construct the central guideway section, launching gantries will be used, which you can see the bases and components for in various locations. These launching gantries will lift the giant concrete girders and allow them to be joined together, tensioned with steel cables, and then glued one after another into a single giant girder that will span between each set of pillars. As you may be able to tell from pictures, unlike in Vancouver or Montreal, guideway segments are delivered in lengthwise units, and each will support only one track - rather than the two seen in the aforementioned metro systems.
Continuing north to the actual Davenport Diamond, the giant steel bridge which has been constructed over the freight line came into view, and I must say it looks much larger and taller in person. Those on the UrbanToronto forum were previously inquiring about whether this bridge section would support four or five tracks on the Midtown Toronto line, but unfortunately it will be constrained to three. All in all, the project is quite impressive - but more impressive is the speed at which work is being completed; the first trains should be running in less than two years.
As always, see my full video on YouTube for more!
You can learn more about the Davenport Diamond in UrbanToronto's dedicated Forum thread where you can also participate in the discussion, or you may leave a comment in the space provided on this page.
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