Here's how Metrolinx built a brand-new elevated rail line through Toronto

The first trains carried passengers along a new elevated stretch of the Barrie Line through western Toronto earlier this month, marking the completion of Metrolinx's new Davenport Diamond Guideway.

Since early April, passengers have been whisked over what was once among the busiest rail intersections in North America via a 1.4-kilometre-long elevated rail line, bypassing the former bottleneck and improving reliability as part of Metrolinx's mission to introduce all-day, two-way GO service.

The guideway's installation between Bloor Street West to south of Davenport Road was an anomaly in Toronto transit construction, in that the project actually came to fruition quickly, and the only delays came in the form of minor hiccups days before its initial intended opening of March 27.

With the line now in use for daily service and the construction dust settling, Metrolinx has released a video detailing the process of building the new guideway.

Early on in the construction process, Metrolinx installed a diversion track, allowing crews to construct the guideway above without interrupting service along the Barrie Line.

The guideway is supported by 54 columns poured to support a structure described by engineering firm Hatch as a "precast and post-tensioned side-by-side double-voided box girder guideway structure."

Progress on the Davenport Diamond on @GOtransitBR is really shifting into high gear. Images from 9am, 10am, 11am & 1pm. The speed with which we're able to build this kind of infrastructure should be instructive for all sorts of transit projects across the City. pic.twitter.com/zEKcW3fNKV

— Urban Cayman (@ProjectEND) July 21, 2022

A total of 170 of these girders were fabricated at an off-site facility before being transported to the build site, where they were hoisted into place using mobile gantry cranes atop steel beams that allowed them to slide forward after hoisting individual section components.

This modular process allowed crews to assemble a new section of the guideway roughly every 36 hours, one of the many factors that helped this project race through construction and into commuter service.