Outside The Box King Road Rail Grade Separation
AbstractThe King Road at-grade crossing of CN’s Oakville subdivision couldn’t be in a worse place from the point of view of the railway, the municipality or the engineering and construction team tasked with designing a constructible grade separation. This section of the Oakville Sub, locally known as “The Throat”, has five separate subdivisions feeding over 100 trains per day through this three mainline track gauntlet. The 80 mph (129km/hr) corridor hosts Metrolinx commuter trains, VIA and Amtrak inter-city passenger traffic as well as the transcontinental and international gateway freight traffic of CN and CP. Further complications include an environmentally protected stream crossing paralleling the track and an adjacent CN freight yard entrance with its associated signal plant.
The design team had to ‘think outside the box’ and proposed an alternate strategy to construct a concrete reinforced bridge structure ‘off-line’ to the south of the location of the grade separation and then slide the entire completed four track bridge into place using an open-cut bridge jacking methodology. This is the first time this method has been used anywhere on the CN network. This methodology minimized the shutdown of the track to a single long weekend, for the entire installation process. This paper will recount the entire process describing the projects constraints and challenges, the technical solutions developed, operational processes and communications and coordination protocols. In addition to the leading edge engineering and construction; success, in large part, can be attributed to careful coordination and commitment to executing the plan exactly in accordance with agreed upon milestones and the flexibility of the design team to deliver solutions through various stages of the projects evolution. The paper will be a valuable tool for anyone faced with getting a large rail bearing structure installed under a very heavily used rail corridor while minimizing train disruption.