By Jon Willing, August 22, 2019
There were two ways the city could get electrified trains through the downtown core when it was planning its east-west light rail system more than 10 years ago: build rail lines on the road surfaces or dig a rail tunnel.
A 2007 report from a task force appointed by former mayor Larry O’Brien, whose council cancelled a north-south LRT contract, recommended a downtown rail tunnel as the best way to breathe life into the core and get rid of the daily traffic bottleneck.
Digging a tunnel through the core of the nation’s capital would be expensive, but there was potential to reduce the operating costs of OC Transpo by taking diesel-guzzling buses off the roads and removing any barriers to getting through a busy downtown at rush hour.
The 2008 transportation master plan included a downtown tunnel as the backbone for the “phase one, increment one” of an LRT system, part of a larger vision to expand rapid transit across Ottawa.
https://ottawacitizen.com/news/local-news/how-ottawa-ended-up-with-a-2-5-km-rail-tunnel-under-its-downtown