Comments on Far From Boring:Meet the Most Interesting Tunnel Boring Machines

By: Jamie

2020-12-17T15:07:44Z

With the recent REM de l’Est announcement, now is a good time for you to revive this blog!

By: Jake

2019-11-24T21:19:02Z

Never knew I wanted to be caught up on Tunnel boring devices, but found this fascinating stuff. Well done.

By: Aidan Stanger

2019-03-11T03:09:16Z

You say “The cost of a TBM doesnâ€™t get much higher as you increase its diameter. Tt is therefore cheaper to build one very large tunnel, rather than two smaller ones” but that doesn’t logically follow, for two reasons:
Firstly, it assumes that two smaller tunnels would be constructed in parallel. Were they instead constructed in series, one TBM would be sufficient.

Secondly, AIUI the cost of the TBM is only a small proportion of the total cost. Other obvious costs include the cost of the crew, the cost of the tunnel linings and the cost of removing the spoil. How do these compare on different sized tunnels?

By: Sam

2018-03-13T17:03:15Z

A lot of people are upset with CDPQ “stealing” the tunnel… And I do understand all the issues and challenges that this will bring mostly on the RTM train service and the potential TGF service that could have used it… Yes “could” because nothing concrete has been budgeted yet for it except new studies (really!?). The truth is that this is an old tunnel that no longer is safe according to current standards. So the hope is that with the REM at least the needed upgrades will be done… Yes building another tunnel would cost a lot but I don’t see how this would be a bad debt. It’s a little upsetting that people in charge seem unable to see the bigger picture when it come to invest in bigger infrastructure. I don’t buy the “it’s too expensive” or “the population is not big enough”…

By: Peter L

2018-03-07T02:05:43Z

Oh! And thanks for the update on tunnel boring, @ant6n! I’m #notamuskfluffer either but hadn’t paid much attention to his tunneling thing (other than to dismiss it) but am glad to see my gut feeling was probably justified.

By: Peter L

2018-03-07T02:03:47Z

Why would you build another tunnel under Mount Royal (ignoring the REM boondoggle) for trains carrying 10s of thousands (maybe) when there are dusty plans for extending Line 5 in multiple directions that would likely carry 100s of thousands of people?

Look at all the bus routes in the “quadrant” between Line 1 and Line 2 (east of Line 2, north of Berri and north of Line 1 east of Berri) that carry 30,000 passengers a day. The Mascouche RTM line is what? A quarter of that?

I’m not a fan of Mme Plante’s Pink line but the area to be served by it is underserved now. Dust off those Blue Line plans … any of them! … and build one of them!

Aside: Looking at STM ridership numbers is fun. They change how the report them every few years, or seem to, and that’s only for the routes you can find numbers for. I also note that they seem to add new routes where there is heavy ridership and that tends to hide the cumulative demand in a corridor – where did those 40k+/day riders on the 67-St Michel go? No idea – not reported after 2008! Where is the “MBTA Blue Book” for the STM?!?!?

By: Fraser Pollock

2018-03-03T17:24:06Z

Affordable is a relative term. Yes, there are things you can do to make tunneling cheaper but at the core of it, tunneling anything is just really, really expensive. Especially, when you have to make the argument to politicians who only see all the other things that this tunneling money could be doing. It’s often a really hard sell to have to make.

By: ant6n

2018-02-25T01:46:04Z

In reply to Sam.

@Sam
Building a second Mount-Royal tunnel would still be quite expensive. It’s not just the tunnelling of several km, but also the very complicated insertion into Gare Centrale. The cost would probably be 1-2billion, which probably doesn’t have a great cost-benefit right now (given that the St-Jerome and Mascouche line are on freight lines and limited by frequency). For now, I’d say it would be much cheaper to share the existing Mount-Royal tunnel, although it would be great if a second tunnel connection had been considered for the future…

By: Sam

2018-02-22T17:53:46Z

@ant6n With the cost of boring becoming more affordable, why nobody is considering a second tunnel under the Mont-Royal? Why not connect Parc Station to Gare Centrale and use it to have the future Via’s TGF, RTM’s Mascouche and Saint-Jerome lines use it? No new station would need to be built in between…

By: ant6n

2018-01-25T19:45:22Z

@Ace
That’s a good point about the issues with stacked tracks. But note that the Barcelona line has ramps between the tracks (see photos of that my article).