Third link: Get down to 80 meters underground for the bus

If that happens, the Quebec-Levis Tunnel could force public transit users to descend to a record depth of 80 meters to board the bus.

Those who want to cross the river on an electric bus, via the “third link”, can do so from the platforms of the “Parliament Hill” station located at an incredible depth, the equivalent of about twenty floors underground.

For comparison, the average depth of Montreal metro stations is 15 meters. The deepest station is Charlevoix, located 29.6 meters underground.

The Édouard-Montpetit station in REM (Réseau express métropolitain) will soon be the deepest in Canada. With its bars 72 meters underground, it will be even the deepest in the world.

Up to 80 meters underground

However, the capital risks bringing down Montreal through the Quebec-Levis tunnel. The Parliament House station, adjacent to Complex G, will reach an approximate depth of “70 to 80 metres,” MTQ confirmed to our Bureau of Investigation. It’s impossible to be more specific at this point.

Two components of the Réseau Express de la Capitale (REC) will converge there, each in its own tunnel: the tunnel’s electric bus and the Quebec City tram line that will also tunnel into the city center at a depth of 15-40 metres.

Retired architect Pierre Brisset, who has studied topographic maps of the area, believes that the station near the National Assembly will be deeper than MTQ claims. Parliament House is located on a rocky plateau 85 meters above river level, he notes.

Slopes from 5% to 6% in the tunnel

Mr. Brisset also stresses the extent of the challenges associated with building the tunnel under the river – worth between $6 billion and $10 billion – due in particular to the rapids. The ministry assured us that the steep slopes “will be in the range of 5 to 6%”.

“150 meters of landing, for this type of structure, I have not seen it anywhere else on the planet.” ”, notes the retired architect, noting that the construction of a bridge for public transportation between the two city centers and two other road bridges to the east, across the island of Orleans, It will save several billions of billions.

The Legault government, which has not yet disclosed any study on the other options analyzed, asserts for its part that an 8.3 km tunnel between the two city centers is the best solution.

One assures us that the steep slopes will not pose a problem, adding that they are “comparable to what one finds on the Henri-IV Highway” between Charest and Hochelaga. Truck drivers will not be able to access the tunnel during rush hour, as indicated, in order to ensure the flow of traffic.

Parliament Hill station depth, for its part, “is not a huge technical challenge,” it is said, because of the experience gained with REM.

The deepest subway in the world

• Pyongyang Network (North Korea): 110 meters
• Arsenalna Station, Kiev (Ukraine): 105.5 meters
• Hongtoday Station, Chongqing (China): 94 meters
• Admiralteyskay Station, Saint Petersburg (Russia): 86 meters
• Victoria Park Station, Moscow (Russia): 84 meters
• Washington Park Station in Portland, Oregon (US): 79 meters away
• Édouard-Montpetit station at REM, Montreal (Canada): 72 meters (*under construction)
• Charlevois Station, Montreal (Canada): 29.6 meters

The longest road tunnel in North America

Much has been said about its width, out of the ordinary and unique on the planet at 19.4 meters, but very little about its length so far. However, the Quebec-Levis Tunnel aspires to set another record, the longest road tunnel in North America.

At 8.3 km, the tunnel proposed by Legault’s government will be twice the length of the current record holder, located in Alaska.

About an hour from Anchorage, the capital of this US state, vehicles and trains alternate on the only track of the Anton Anderson Memorial Tunnel, which is about 4.2 km long.

Elsewhere in the world, particularly in Asia and Europe, nearly fifty road tunnels have already crossed the 8-kilometer mark. The longest of them, the Lerdal district of Norway, is built at a distance of 24.5 km.

However, tunnels dedicated exclusively to the passage of trains are in a class of their own. One of the most famous, located under the canal (between France and England) is more than 50 km. The great hero, the St. Gotthard railway tunnel in Switzerland, covers an impressive distance of 57.1 km.

‘Very dangerous’ project

Engineer Bruno Massicot is among those who are openly skeptical about the choice of an under-river tunnel linking Quebec and Levis, a “highly dangerous” project, he says.

The technical challenges of this huge project – which has the potential to break many records globally and in America – will be many. He warns that although the obstacles cannot be overcome, they will come at a heavy cost.

“It’s big… at some point there is a limit to the technology push. Yes, we can go to the moon, but it’s expensive. Anything is possible, it’s just a matter of costs.” […]If we want to do something economical, a large tunnel (with a single tube 19.4 meters in diameter) is probably not the best solution,” says the expert from the Polytechnic of Montreal, in an interview.

Bruno Massicot knows what he’s talking about since he conducted a tunnel feasibility study in 2016 on behalf of the Couillard government. Five years ago, the only pass studied – at the request of the MTQ – was located in the far east, under the tip of Ile d’Orlian.

Mr. Massicott concluded that such a project, the “risky” he had already insisted on, would be possible for about $4 billion. Remember that the current project, linking downtown Quebec City and Levis, could cost up to two and a half times as much.

Two tunnels instead of one?

The engineer also had a mandate, at the time, to focus exclusively on a project of two parallel tubes rather than a gigantic six-lane monotube on two floors, which would be the widest in the world.

“To beat a record like that, you really have to have a need and be sure that it is absolutely the only solution and that this solution will be very profitable. That is why I am talking […]I have great doubts. ”

Like retired architect Pierre Brisset, Mr. Massicott also argues that securing a two-level tunnel, with entrances and exits, is much more complex. He says that even government engineers refused to consider the monotube option five years ago.

“It is necessary that both requests be made: a large tunnel or two parallel tunnels,” he suggests. It can happen that two tunnels cost much less and are less dangerous than a large tunnel. “