Calgary Transportation planners have recently disclosed the the original plan for a deep tunnel underneath the Bow River will no longer be proceeding ahead due to geotechnical analyses under the Bow River indicating substantial risk. As we have said before, we are no engineers, but we presume this to potentially mean unstable soil conditions as a result of the river’s location.

In light of this recent news, there appears to have been fears on behalf of many Calgarians with worries that the project may suddenly be in jeopardy, ranging from a return to the surface through downtown and along Centre St., an elimination of the north-central portion of the line, or a halting of the project altogether. We wish to dispel these fears by providing a short overview of what is ongoing within the city centre. What we will show you is that it is unlikely the North Central portion will be cancelled, let alone the entire line, and that Calgary Transit appears to continue to be planning (and constructing) for tunnels underneath the Beltline and downtown core.

Bow River Options:

Though current news reports are vague, the city appears to have still discounted three of five options for moving the Green Line through the core. We base this on the knowledge the city has so far not informed the public of changes to the 2nd Ave. SW underground station, suggesting the line will still pass through this area underground. These options include an elevated line over both the river and city centre, as well as an option to keep the line at-grade beyond 2nd Ave. SW with a river crossing via the existing Centre St. bridge. These Obviously the city has also discounted the option of a deep bore tunnel underneath the river. You can view these old options here. PLEASE NOTE: Though all images indicate a station at 9th Ave. N, and a mix of options through the Beltline, the 9th Ave. station was removed due to cost considerations early into planning, and plans for the Beltline portion remain unchanged.

This leaves two options remaining. The first is for a brief portion of track at-grade near the river, with the LRT transitioning to an overpass, prior to going underground south of Crescent Rd. This means the LRT will travel underground from the Bow River bridge all the way to 23rd Ave N.

The other option which appears to remain feasible is for a bridge starting from near 2nd Ave. SW which delivers the LRT on to Centre St. after the river, with a tunnel from 12th Ave. to 23rd Ave.

In both cases, the LRT will still travel underground through downtown and continue to 16th Ave. N This means no traffic impacts during the regular operations of the LRT.

Centre St. Traffic:

Along Centre St., within Option B, traffic will be impacted no more than if the LRT were to travel underneath the Bow River, as the LRT will remain underground. This also allows for 4 lanes of traffic to be retained underneath Centre St. From 40th Ave. N to 23rd Ave. N, the LRT will continue to travel at-grade under current plans, and will force Centre St. to go down to two lanes. Four lanes will be retained from 20th Ave. to downtown.

Within Option E, traffic impacts will be more substantial. From 12th Ave. to the Centre St. bridge, Centre St. will be forced down to two lanes as the city does not own land to allow for the widening of Centre St. Additionally, should the city choose to purchase the land, several building demolitions would be required. We also posit that should the LRT run at-grade in this area, crossings from 9th Ave. to 11th Ave. would be closed, with the LRT running in the middle of the roadway trough to the tunnel between 12th Ave. and 20th Ave. N.

Tunneling Costs:

Though the LRT is being returned to above-ground across the Bow River, cost savings are relatively slim, assuming the Bow River Tunnel and new Bow River Bridge options are both at the top of their estimated expenditure categories. Calgary Transit estimates rail to cost 250 million when underground, and 100 million when elevated. Using Google Maps, the distance of the original Bow River tunnel to Crescent Rd. is approximately 500 metres. This will save 75 million on phase one of the Green Line.

This means at best, an additional kilometre of line can be constructed. Assuming Stage 1 construction will include the full tunnel to 23rd Ave. N, the Green Line can be extended to 32nd Ave. N in the north (one stop further, to the 28th Ave. N station). To the south, this could mean a one station extension to Prestwick. However this option is the least of likely of the two, relatively unlikely options, as a tunnel is required under 130th Ave. N. What is more likely is that additional costs will be faced through the extension of construction to 2027 due to the Bow River crossing delay.

The Beltline:

We do not believe the Beltline portion of the Green Line is in any more jeopardy than the remainder of the line. Construction has already started on utility relocations along 10th Ave. SE, and city council has approved the location of the line. This suggests Calgary transit is well prepared to continue tunneling through the Beltline.

Opening Delays:

Unfortunately, city council recently suggested the Green Line opening may be delayed by one year, in large part due to the technical difficulties faced with the Bow River crossing. Because of difficulties in crossing construction, the planned start date of construction along this stretch is now 2021-2022. However, we believe it is possible for part of the line to open on time. Because the Shepard LRV maintenance and storage facility remains on track for completion, as does the souther portion of the LRT line, it is possible Calgary Transit may be able to open the line by 2026, at the very minimum, up to the 4th St. SE station. In fact, the city may be able to open further to the Centre St. station, depending partly on whether the tunnel to that station will be bored or constructed via a cut-and-cover type method, and mostly on the proposal put forward by construction companies. The new request for proposals put forth by the city envisions one construction company will focus on the downtown tunneling portion, while another will focus on the southern leg from 4th St. SE onwards.

Conclusion:

Overall, the Green Line appears to be in for a delay, at the very least, for the inner-city portion. However, we think it is unlikely the city will cancel the project (at the present stage), and equally unlikely the city will re-split the north and south portions of the project. All options currently being considered continue to include a tunnel to an underground 16th Ave. N station as well as underground stations within the downtown. The Beltline portion of the Green Line remains on schedule, and is in fact undergoing enabling works. The only change in the project is the Bow River crossing, and whether the LRT will travel along Centre St. vs returning to a tunnel once across the river. Our evidence (which, admittedly, is quite weak) would suggest a continuation of the tunnel from Crescent Rd. to 16th Ave. N would be best for traffic and LRT speeds. However we await the release of the full city report.