Dear Councillors McKelvie, Lai, Karygiannis, Thompson, Ainslie and Crawford
Many of you support building the Sheppard Subway and the Scarborough Subway Extension. So do we.
But none of us want to see huge parts of our city destroyed by the TTC for 5, 6 or 7 years while they build stations with their ‘cut and cover’ technique.
We want you to please move a motion at the next TTC Board meeting.
Please ask Staff to report back on the issues and opportunities raised in this letter.
This is how the TTC builds stations
on a subway line.Can you image this along Sheppard…
at Victoria Park, at Warden, at Kennedy…
all at the same time…for 5, 6 or 7 years!
Is there a better way?Can we get a subway system without destroying our communities and businesses?
The answer is YES and experts in the TTC and their tunneling consultant Hatch know all about it.
Edward Poon of the TTC and experts from Hatch went to the North American Tunneling Conference in Washington D.C. this past June. They presented a paper advocating a better way to build subways. Their conclusion:
While the cost of a large diameter running tunnel between stations is higher
compared to twin tunnels, the savings in the avoidance of cut and cover construction (stations
and track cross-overs) more than offsets the larger tunnel cost in the running structure.
The estimated project cost saving at this very preliminary stage was approximately 25%
of the capital cost.
What are they talking about? We call it the Barcelona Technique because that’s who pioneered it.
The TTC has typically built our subways by boring out two tunnels running parallel using tunnel boring machines [TBM’s] of 6 meters diameter. That’s how they built the recently opened Spadina-Vaughan subway extension. For the Scarborough Subway Extension they are thinking about using a single larger TBM of around 10.7 m diameter.
The single 10.7m TBM excavates maybe 60% more earth but saves the cost of building passageways between the twin tunnels for cross over tracks, service and emergency passages.
The Barcelona Technique takes this one step further. It uses a 13m diameter TBM. That’s wide enough for trains to run side by side, do all the cross over tracks and emergency passages they need AND… the key benefit…at stations, one train can run on a deck above the other, as shown in the diagram below.
There are three HUGE advantages
1. No ‘cut and cover’ excavations at stations = ZERO disruption to the street above;
3. With a little forethought future stations can be opened later if there is not sufficient demand today.
None of this is possible with the TTC’s ‘cut and cover’ station building technique.
construction. They are building the deck within the tunnel so one train can run above the other. This will become a station when they’re done.
They can build major portions of the stations while the TBM continues up ahead excavating the rest of the tunnel.
They can build major portions of the stations while the TBM continues up ahead excavating the rest of the tunnel
How do people get down to these new stations? You acquire a property next to the street and excavate down and then laterally into the station. The shaft handles escalators/elevators, emergency stairs, plus all the pipes and wires needed for the new station. ZERO disruption to the street.
They are excavating the shaft down to track level beside the street for the escalators, elevators and emergency stairs.
Canadian tunneling companies are way out in front of this industry: they just pioneered boring a diagonal shaft for escalators down to the Moscow subway. Can we do that here?
What do other tunnel building experts say about the Barcelona Technique?
Here’s what AECOM’s chief tunnel engineer Verya Nasri says:
Both the time savings and minimization of roadway right- of-way disruptions, due to cut-and-cover construction, translate into significant construction cost savings and a more manageable public relations effort.
Here’s what Michael Schatz, Managing Director of Hatch says:
You get a better solution for less cost.
Is any other city using the Barcelona Technique?
Yes. Just this past year alone, the cities of Calgary and San Jose-Bay Area Rapid Transit systems researched everything you could possibly know about subway building and chose the Barcelona Technique. They did not want to tear up their downtowns for 5, 6 or 7 years.
What’s the catch? If TTC Engineers know all about this why haven’t they told us?
It costs more to excavate a large diameter tunnel. The savings come when you build stations.
It’s a clear winner for extending the Sheppard Subway with perhaps 5 or 6t stations along the way to Scarborough Centre.
For the Scarborough Subway Extension, they have knocked out all possible stations along the route.
Take away the stations and there can be no savings! But no-one in the whole world has ever gone to the expense and disruption of excavating a 6 kilometer subway tunnel…and built no stations along the way! We will be the laughing stock of the world subway building industry.
Serve the people of Scarborough: put the stations back on this line at Lawrence and at Eglinton-Danforth. If someone persuades you there is not enough demand at present for these stations, the Barcelona Technique allows you to ‘rough’ them in. They can be opened later with minimal disruption when demand warrants. You can’t do this with the TTC’s inflexible cut and cover technique.
You need to hear from Edward Poon, Verya Nasri, Michael Schatz, the people from Calgary, San Jose/BART, and Barcelona. They believe the Barcelona Technique is the ‘better way’ to build subways.
Please put this letter on the agenda of the next TTC Board meeting.
Please move a motion directing staff to give you a full and fair comparison of the Barcelona Technique versus the TTC’s typical ‘cut and cover’ way of building subways
Lorne Ross for the Glen Andrew Community Association.
CC: Luke Robertson, Chief of Staff, Office of the Mayor.