The western extension of the Crosstown LRT will be built about 10m north of Eglinton Avenue at the Humber valley. Most of the LRT is underground, including here in Mount Dennis and again west of Scarlett Road. Although tunnels are well waterproofed and often pass under rivers, Metrolinx decided to elevate the section across the valley.
The entrances to two stations (at Jane and at Scarlett) would have to be raised above flood levels. Construction of the station boxes below the water table , the very deep shafts needed to allow ventilation and access via emergency stairs, escalators, and elevators would all add significantly to the costs, but still be risky given the probability of a failure in the next hundred years caused by a sink hole, other earth movement, or corrosion.
The elevated solution also means trains don’t have to dive and climb, which reduces operating costs and also travel time.
MDCA reluctantly agreed that a tunnel under the Humber was not a good business decision.
You can learn more about Crosstown West extension at http://www.metrolinx.com/en/greaterregion/projects/eglinton-crosstown-west.aspx
and read about our September 25th walk at https://blog.metrolinx.com/2021/09/29/metrolinx-heads-into-the-valley-with-the-mount-dennis-community-association/