As part of the GO Expansion plan, Metrolinx had intended to grade separate the junction at Scarborough Station on the Lakeshore East corridor to eliminate the conflict between frequent service on the Stouffville corridor which runs north, and on the Lakeshore line itself. Plans call for frequent, electrified service on both corridors. All Stouffville and about half of the LSE trains will be electric. Some diesel operations will remain on LSE for trains that will run beyond the end of planned electric territory at Oshawa.
Approval for this project was granted at the end of February 2021.
The Environmental Project Report for the Scarborough Junction Grade Separation TPAP was available for public review from December 22, 2020 to January 20, 2021. It has been reviewed by the Minister of the Environment, Conservation and Parks. The Statement of Completion has been issued, and the project can now proceed to the detailed design and implementation phase.
Source: GO Expansion Program Website
Here is a map of the junction as it appears in the Environmental Project Report:

Four consortia were prequalified for the GO OnCorr project in May 2019, and the RFP process closed on November 30, 2021. The successful bid will be announced sometime in 2022. The consortia include major international rail operators including SNCF (France), MTR (Hong Kong), RATP (Paris) and DB (Germany).
In April 2021, transit video blogger Reece Martin posted an interview with Metrolinx CEO Phil Verster on a variety of topics. Verster talked about a shift in how major contracts are handled including early involvement of proponents in the design phase. The portion of interest includes the following exchange which has been edited only to remove pauses and add punctuation.
PV: Let me give you an example Reece. Just practical examples speak a thousand words for me.
RM: Sure.
PV: We have three big projects overlapping at the new East Harbour Station that we are working with Cadillac-Fairview and the City of Toronto to get built in the Docklands area. And the three projects are: GO expansion, we want more trains on the Lakeshore East; the Ontario Line is going to have platforms at East Harbour; and then we want to build East Harbour itself which is going to be the Union Station of the east. So these are three massive projects that are intersecting.
From the really quality work that we got done by our GO Expansion team, it was evident that if we had a third platform, sort of a centre platform, in the station, we could increase the capacity of trains that can stop at East Harbour by about 8 trains per hour at the peak higher than the 12 trains we had intended. So we can now stop 20 trains an hour rather than just 12, and that 20 years from now when capacity gets constrained at Union Station, we will have saved 2 of the 16 roads. We would have freed up by having this platform in terms of reducing the switchover times between lines which then occupies capacities. So we make in effect 8 trains on 12 increase in capacity at East Harbour, we save 2 platforms out of 16 at Union Station.
But more than that at Scarborough Junction by putting a centre platform at East Harbour, a couple of kilometres down the way at Scarborough Junction, we can now avoid building a rail grade-to-grade separation which saves us $140 million.
RM: That big flyover that you guys had planned before.
PV: Exactly. Now that’s not required because of a station design choice we made further upstream that benefits Union Station as well as East Harbour as well as to the east [?].
You see this is innovation. Now this sounds really boring perhaps for other people that are not sort of rail geeks like people like you and me, but I’m telling you this is unique stuff and it’s super exciting to make these changes. I call these once in 60 year, once in 100 year type decisions that we are making now that will massively benefit this network 50, 60 years from now.
Talking Transit with the CEO of Metrolinx, posted April 15, 2021
It is quite clear that Metrolinx had a revelation about its proposed design for the LSE corridor almost a year ago, and this reflects various design changes that have occurred along the way.
- Originally, at East Harbour Station, the Ontario Line would have “straddled” the GO corridor with the eastbound OL track on the south side, and the westbound OL track on the north side. This would have permitted across-the-platform transfers with “local” GO trains running on the outer pair of tracks while the express trains ran through on the inner pair. This arrangement was touted in an October 2019 Metrolinx blog article that remains online.
- The straddle option turned out to be problematic not just at East Harbour, but further up the GO corridor at Riverside/Leslieville and Gerrard OL stations which would be much more complex with split platforms, as well as the need for two portals at each end of the surface-running OL segment from west of the Don River to Gerrard Street. Metrolinx abandoned this scheme, and shifted the OL to the north side of the rail corridor. The across-the-platform transfer, previously thought to be essential, was abandoned.
- This change allows all train-to-train interchanges to occur at a concourse level under the tracks much as at Union Station. In turn, that also makes possible a platform arrangement with stopping by all GO trains, not just those on two of four tracks.
- From a rider’s point of view, it does not matter which track a particular GO service uses, and it is a short step to allocating pairs of tracks to each of two services, rather than to local and express trains. That eliminates the need for the grade separation at Scarborough. (There are implications for Danforth and Scarborough Stations, but that’s a separate matter.)
This is all very interesting stuff, although I would hardly use the term “innovation” to describe moving away from the original straddle design (something else that was an “innovation” in its time) that way. One might ask why it took Metrolinx so long to come up with this scheme and, in the process, simplify operations, increase capacity and reduce project costs.
In a recent Twitter exchange, I asked Metrolinx to confirm or deny that the grade separation had been removed from the project. The GO Expansion team replied:
The reference concept includes minimum service level requirements – how the winning proponent chooses to do that (which grade seps to build, trains, signaling, etc.) is up to them. The contract is designed to spur market innovation in this way.
Metrolinx has completed the necessary TPAPs for all potential grade seps, so needed approvals are in place for financial close, expected in the first half of this year. Once the proponent is on board, we can confirm with certainty which grade separations will go forward. 2/2 ^pp
Tweets by @GOExpansion, January 4, 2022
In other words, the design is up to the winning proponent, even though everything on the Metrolinx website still claims that the grade separation is part of the plan including this October 2020 article in their blog which has not been removed or amended.
Twitter is not an ideal place to get into technical discussions, and it was also obvious that reconfiguration of the platforms and track allocations would have other effects at East Harbour. Therefore, I wrote to Metrolinx seeking clarification of their position.
As presented in all of the consultation materials and discussed in an article on the Metrolinx Blog, there will be a flyunder at Scarborough Junction where the outer eastbound track will connect to the Stouffville corridor via a grade separation to eliminate the conflict with through service on the Lake Shore corridor.
In an interview with Reece Martin on YouTube, Phil Verster talks about a change in the configuration at East Harbour and at Scarborough Junction that eliminates the need for the flyunder and increases capacity at Union Station. Although he does not go into the details, this implies that the allocation of LSE corridor tracks to services will change so that the Stouffville trains will use the northern pair of tracks and the LSE trains will use the southern pair. Coupled with an added platform at East Harbour and through-routing of services at Union, the capacity of the combined corridor is improved by reducing train conflicts and by improving operations at Union.
This is an interesting idea, but when I raised, via Twitter, the question of why it was not reflected in published materials, the response from the GO Expansion team was that decisions on configuration were up to whatever proponent is selected for the GO OnCorr program. That directly contradicts Phil’s enthusiastic statement that this change is happening and the decision has already been taken by Metrolinx.
The only way to reconcile these positions is to say that Metrolinx has not actually “decided” on which configuration to use, but will “suggest” the new scheme as an option for bidders. Alternately, one of the bidders already came up with this idea as part of the work on their proposal evaluation and Metrolinx has embraced it unofficially.
Can you clarify what the situation actually is?
Email from Steve Munro to Metrolinx Media Relations, January 6, 2022
Changes at East Harbour station have ripple effects, and I pursued these questions as well:
There are implications at East Harbour on a few fronts.
First, does the proposed added platform that Phil mentioned alter the alignment of tracks crossing the Don River, and what does this do to the GO and OL bridges and any early works including the Ontario Line alignment?
Second, with the new hook-up of services running through at Union, is there still a need for electrification of the Bala Subdivision (GO Richmond Hill) as a turnback facility, or will you no longer have a service that only runs west from Union and needs that turnback?
Third, one of the rationales used for the Don Valley layover has been the loss of capacity in the existing Don Yard (aka Wilson Yard) due to other projects by which, I assume, you mean the Ontario Line construction. Originally, in the straddle configuration, the OL would have had two portals one on each side of the corridor, but now it has only one on the north side. How does the revised geometry work for the existing yard tracks, the bridges, the OL portal and the connection to the Bala subdivision?
Email, op. cit.
Metrolinx replied:
Hi Steve,
We don’t have any further information to share beyond what the GO Expansion account replied. For further updates, stay tuned to Metrolinx News.
Email from Fannie Sunshine, Advisor, Media & Issues Communications, Metrolinx, January 6, 2022
And there the matter sits. Phil Verster gives a gung-ho interview about innovative design eight months ago, but nothing on the Metrolinx website reflects his comments. A request for detailed feedback nets a “stay tuned” answer.
This whole exchange begs a more delicate question: to what degree can project designs be changed at the behest of the P3 proponent after all of the public reviews are completed based on a proposed design? What other changes might be in the works for any Metrolinx project, and will they just happen without any review or consultation?
To me, the proposed change in track allocation on LSE makes sense, but why is it such a secret?









