Opinion: UBC SkyTrain should be built with cut-and-cover tunnels | Daily Hive

Opinion: Cut-and-cover tunnel construction should be considered for UBC SkyTrain to save money

Cut-and-cover construction on Cambie Street for the Canada Line in the late 2000s. (Canada Line Photography)

Written for Daily Hive Urbanized by North Vancouver resident and public transit and active transportation enthusiast Johnathan French.

I like it when my tax dollars are spent efficiently. That’s why I strongly believe we should build UBC SkyTrain extension’s tunnelled segments using the cut-and-cover construction method, even if it means more disruption.

This might sound sacrilegious, considering all the kerfuffle that happened last time we did this with the Canada Line. Businesses were affected, and some shut down because of the construction.

But you know what? The Canada Line was built at a reasonable cost and even ahead of schedule. The entire 19-km-long line with 16 stations cost about $2.1 billion back in 2009. Part of how they were able to achieve this low cost is that they chose the best and most efficient construction methodology for the job, and for large swaths of the line, that meant building cut and cover.

Based on the most recent route concepts — previous preliminary planning work conducted by TransLink — it looks like this westward extension of the Millennium Line from Arbutus to the University of British Columbia (UBC) will be mostly underground, if not completely. While I would personally prefer an elevated alignment for the views, I think cut and cover is the overall best choice for the route, and I’m worried the provincial government — which took over the project’s design, planning, and implementation responsibilities from TransLink in September 2022 — might overspend on tunnel boring machines to avoid disruption.

You might also like:

Cut and cover involves digging an open trench and then covering it up when finished. It’s a simple way to build tunnels, one that we’ve been using for thousands of years.

But in recent years, we’ve largely stopped using cut and cover, mainly for political reasons stemming from the Canada Line’s controversy. Cut and cover disrupts businesses and residences along the line during construction, whereas the more common tunnel boring method avoids this by only requiring disruption where the stations are.

There are certainly cases where tunnel boring machines make sense, but they don’t make sense for the UBC SkyTrain extension.

For one thing, it’s not like tunnel boring machines are a magic bullet to shield us from disruptions and business closures; just look at the current project of building the Millennium Line’s Broadway extension to Arbutus. When you build with tunnel boring machines, you still need to dig things up. You still need station boxes — akin to localized cut and cover — and they need to be much bigger to account for the increased depth. You still need to disrupt businesses.

broadway subway tunnel boring machines skytrain millennium line

Tunnel boring machines “Elsie” (left) and “Phyllis” (right) for the SkyTrain Millennium Line Broadway Extension, October 2022. (Government of B.C.)

canada line cut and cover construction cambie

Cut-and-cover construction on Cambie Street for SkyTrain Canada Line in the late 2000s. (Canada Line Photography)

With cut and cover for the length of tunnelled segments, where appropriate, you will disrupt more businesses, but for less time. On its own, that’s a tough choice, except for one thing: cut and cover costs way less.

Again, it’s not that cut and cover is always the best solution. The Canada Line was built with a variety of different methods; sometimes the line is elevated (in Richmond and at the airport), sometimes it’s on the surface (at the airport), and sometimes it uses tunnels built with tunnel boring machines to traverse complex areas (in downtown Vancouver and under False Creek).

There might be good reasons to use tunnel boring machines or elevated guideways for parts of the remaining Millennium Line route to UBC, like perhaps traversing from one parallel street to another. That said, cut and cover is clearly the least expensive option for most (if not all) of the route, as long as we don’t mind a bit more disruption.

Let’s start with what that disruption might look like. When the Canada Line was built, the cut and cover sections required the closure of up to four lanes of vehicle traffic. Let’s assume we’ll need about this much space throughout the project.

Starting at the intersection of Arbutus Street and West Broadway, where the under-construction Broadway extension terminates and the new Arbutus Station will be located, this corridor has at least a 19-metre roadway width of traffic lanes and street parking — all the way from Arbutus Street to Alma Street. That’s enough to leave two lanes open and all the sidewalks intact.

From Alma Street to Wallace Crescent, there are two blocks of residential streets. These are smaller, so we would need to fully close these streets for a few years of construction. There are no driveways, and there is plenty of on-street parking nearby (not to mention back alley access to most houses). We could keep the sidewalks open, and we wouldn’t have to cut down a single tree.

From Wallace Crescent to Trimble Street, there’s plenty of park and green space off to the side to temporarily work with, and from Trimble Street to Blanca Street, the only driveways are for two churches, both of which are accessible via the alley.

Google Maps

If we want, we could go above-ground starting at Blanca Street (especially if we want to make more of the SkyTrain flood-proof), or just continue cut and cover; either option is way cheaper than using tunnel boring machines for the entire route to the UBC campus.

The final stretch to UBC is the easiest part. The best option is probably to connect to University Boulevard, going straight through the golf course. Once we reach University Boulevard, there is a large median, ideal for cut-and-cover construction.

Ideally, we could build at least two UBC stations (it’s a big campus after all), and leave some room for an eventual extension to 41st Avenue.

This obviously doesn’t need to be the exact route we go with; for example, from the intersection of West Broadway and Alma Street, we could go down to West 10th Avenue and then connect to the median along University Boulevard (though this would avoid the future Jericho Lands development). I would also love at least part of the line to be elevated, just not at the extra cost of hundreds of millions of dollars. We would have to see how it pencils out.

translink ubc skytrain route options april 2022

Sasamat Station vs. Jericho Lands Station route options for UBC SkyTrain, April 2022. (TransLink)

UBC SkyTrain route options for a second station reaching south campus, near Wesbrook Village. (TransLink)

Johnathan French/Google Maps

Regardless, the point is clear: a SkyTrain extension to UBC that is largely achieved through the cut-and-cover methodology is viable, with plenty of route options to choose from.

Would cut and cover be disruptive to the people who live and work along this corridor? Of course. However, the current 5.7-km-long Broadway extension to Arbutus is costing taxpayers almost $3 billion, or around half a billion per kilometre (assuming costs don’t go up again). If we were to pay a similar cost for the UBC extension (around seven km), it would cost us at least another $3.5 billion today.

The Canada Line cost $2.1 billion to build in 2009, or $3 billion if we adjust for inflation. That’s an average of $158 million per km; if we are to go by this rate, we would construct the entire seven-km-long UBC extension for $1.1 billion.

It gets bette,r though. The Canada Line needed to use tunnel boring machines for the northern parts of the route. They needed a complex flyover to branch off to the airport and Richmond. They had to build in the heart of downtown Vancouver, they had to go under False Creek, and they had to construct two bridges across the Fraser River.

The UBC extension will do none of those things. If we’re smart about this, we could achieve a cost-per-km even lower than that of the Canada Line.

We will not achieve such a low price using tunnel boring machines. For one thing, this equipment is expensive. They need specialized workers. You also must excavate big station boxes, deep underground. Because the stations are bigger, you need more escalators and staircases, more space for emergency exits, more ventilation, etc.

With cut and cover, stations are built just under the road surface. This makes them far less complex to build, which leads to a much more competitive bidding process. Any local construction firm that can operate excavators can submit bids, as opposed to the relatively limited number of global firms that are familiar with tunnel boring machines.

More competition for bidding not only drives down prices but also allows more small businesses to bid, as opposed to the usual giants.

Having the stations right below ground also makes them much more accessible to the public. Instead of going down into a concourse and then down another escalator 15 to 20 metres below the surface, what if you just had to go down one level? This doesn’t sound like much, but it makes a big difference when you take the train every day — and these accessibility benefits of a shallow subway station design can be seen with the Canada Line’s four cut-and-cover stations under Cambie Street.

Long-term, it’s also a lot less to maintain. Fewer escalators, lights, ventilation fans, etc., mean fewer ongoing operating and maintenance costs.

Cut-and-cover construction on Cambie Street for the Canada Line in the late 2000s. (Canada Line Photography)

In summary, cut and cover tunnels are significantly cheaper to build and maintain. They can also be built much quicker, with more local construction companies, and they’re better for passengers. Isn’t that worth the cost of disruption?

B.C. is facing a budget crisis, one that will only get worse in the coming years. We also desperately need to build more quality rapid transit, but we won’t be able to afford it if we cannot keep costs under control.

Yes, many cities around the world have built underground metros for cheap using tunnel boring. Madrid famously built much of its metro this way for an astonishingly low cost, though this was in large part thanks to its efficient planning processes.

We used to have the capability to build at a reasonable cost, even for complex projects. The 11-km-long Evergreen extension of the Millennium Line was finished in 2016, a bit late but under budget, at a cost of about $1.4 billion, or $127 million per km ($162 million when adjusted for inflation). That involved a two-km-long tunnel bored segment up to 50 metres deep, squeezing the line in between an active railway and a busy street, a satellite operations and maintenance facility for the trains (called OMC3), and seven stations, including the major expansion of Lougheed Town Centre Station.

By comparison, the under-construction, 16-km-long Surrey-Langley SkyTrain extension of the Expo Line will now cost taxpayers about $6 billion, or $375 million per km. That’s for a relatively simple elevated line along Fraser Highway with eight stations and no tunnels.

Clearly, the methodology we use to build our infrastructure is only one part of the solution to our budget woes. Canada has a huge problem when it comes to project management. Our construction costs are actually comparable to those of other large cities around the world, but we need to address the systemic issues plaguing how we plan and deliver our infrastructure projects.

One of these issues is mixing politics with infrastructure planning. Politicians like to avoid making people upset, even if it means wasting billions of taxpayer dollars; the $13 billion Eglinton Crosstown light rail transit project in Toronto is a great example of this, and should serve as a warning.

Let’s try to avoid those political pitfalls; let’s choose the most cost-effective construction methodologies and technologies for the job.

If we play our cards right, we could save billions of dollars, which could help fund more public transit projects, like a downtown Vancouver streetcar network, a gondola to Simon Fraser University’s Burnaby campus, or the North Shore SkyTrain.

You might also like: