After a slight hiccup in the planned opening timeline, a new elevated train line through Toronto begins operation this week.

Metrolinx had initially planned to begin service on the new 1.4-kilometre-long Davenport Diamond Guideway on March 27, capping off the infrastructure's rapid construction between Bloor Street West and Caledonia Park Road in western Toronto.

So when that date finally approached, and Metrolinx suddenly needed more time, it came as a bit of a surprise — even in light of the much-publicized delays on the transit agency's more prominent Eglinton Crosstown LRT project.

Metrolinx announced less than 72 hours before the planned start of service that "the opening of the Davenport Diamond Guideway is postponed," citing the need for "additional tests, training, and procedures prior to running revenue service trains on the guideway."

A week later, the project is now completing that testing and training, and gearing up for the guideway's opening for service on Tues. April 4.

Testing of the Davenport Diamond @Metrolinx courtesy of @CBoomhour pic.twitter.com/z6wddk4vF8

— Christine Boomhour (@Osheafan) April 3, 2023

The project's forthcoming completion overcomes a significant barrier in Metrolinx's plan to introduce all-day, two-way GO service on the Barrie Line, by bypassing its at-grade intersection with the CP rail tracks carving east-west across the city.

On Saturday, crews began connecting tracks between the Barrie Line and the new guideway that a portion of the route will soon operate on. This work is expected to be complete by Monday, clearing the way for the first passenger trains will speed along the guideway the next morning.

Tracks are being connected to the Davenport Diamond elevated guideway this weekend! pic.twitter.com/xo4CfH8MRV

— Jamie (she/they) (@TransitThinker) April 2, 2023

Other preparations for the route upgrade are being carried out on Monday, including an emergency exercise being carried out along the guideway.

Starting at 3 p.m., the four-hour exercise will see emergency services crowd the area, including a full Metrolinx Incident Command team in a simulation of an emergency.

Continued progress on the Davenport Diamond Guideway: Running test trains before the start of revenue service trains. Stay connected for more updates. pic.twitter.com/qvbMeAkLnm

— GO Expansion (@GOExpansion) April 3, 2023

Opening of the new guideway advances Metrolinx's plan to upgrade service along the Barrie Line with all-day trains at intervals of 15 minutes or faster.