Highway 7 - Kitchener to Guelph

[ijmorlan]

So apologies if this has been asked/explained elsewhere... but everytime I drive by this area I have the same question.

How do we build the two Wellington/Shirley connector roads under the railway without disrupting our (hopefully increased) service?  Every other overpasses I have witnessed being constructed, the railway snakes around until the underpass is built then rail lines straightened out.  With this one, there is a highway bridge that prevents just moving the line off to the side.

I assume they may just close one of the two doubled lines at a time, but having excavation work that close to the second line I would of assumed as being risky.

Any experts?

Coke

Not an expert, but interested. There are lots of ways of building bridges and tunnels in difficult situations. One approach is to build the tunnel structure and then shove it in place under whatever is on top, thereby avoiding significant interruption to what is on top. I don’t know if they can literally ram the tunnel in without interrupting service, or if they can perform ramming operations when train service isn’t running, but I have definitely heard of this sort of operation being done. Another potential technique might be to close the track for a long weekend, remove the portion of track above where the tunnel will go, pour a reinforced concrete slab, and re-instate the track. Then complete the rest of the project by working under the concrete slab. This technique might be doable one track at a time, which could avoid any complete closure of the line.

It would take an actual engineering study to assess the feasibility of these ideas in this circumstance, and of course an actual civil engineer would have other methods at hand that they could choose.