Building transit in a dense urban environment takes a lot of planning. Long before tracks are laid and trains start rolling, you need to lay the groundwork – literally. As the province moves forward with the GO Expansion program – a region-wide increase in GO train service – here’s an inside look at how the labyrinth of pipes and wires below ground, as well as overhead, can become an engineering question that needs to be solved.
It’s the ever-connecting world we take for granted, and often lose sight of.
From electricity to internet and from running water to sewer connections – a complex network of utilities stretches right across our region and then beyond. On their way to your home, some run along above-ground wires, while others are encased in pipes or conduits buried underground.
Some of these utilities cross existing railways and many of these pipes and wires actually run right within railway corridors, a relatively straight shot to move essential services between regions. Of course, there are pros and cons to this. On the one hand, this means they interact with a host of railway assets, including signalling and telecommunications lines but, it also minimizes the impact to road traffic.
What lies below and what hangs above are crucial questions for any construction project. The innocuous suddenly becomes a problem. In case of a program as vast and complex as GO Expansion, that stretches across the Metrolinx-owned sections of all five GO corridors, rail lines which in some cases are more than a hundred years old, this is a very complex undertaking.
Leaning on years of experience with geotechnical, tunneling, utilities and transit infrastructure work, Lindsay Lashley knows the importance of starting this kind of work early.
“Because of the long lead time involved with coordination of every potential conflict and the complexity of the overlapping designs, Metrolinx has been leading the way on facilitating this work very early in the process,” Lashley, Metrolinx, Senior Manager Early Works Group explained.
“My group’s role is essential to managing the risk associated with potential delays and any possible unknowns we may uncover during our investigative work or during actual relocations.”
Metrolinx is dealing with literally hundreds of confirmed and potential conflicts between future GO Expansion infrastructure and existing utilities belonging to more than 20 companies. Addressing these conflicts now means that future work can proceed with less risk of schedule delays and cost increases. The exact scope is continually evolving and respective utility relocation designs are coordinated as the infrastructure requirements for GO Expansion become clearer.
How does utility relocation work?
Once the design is complete, detailed work plans are prepared for Metrolinx regarding any work that is required within the rail corridor.
- Crews physically locate the precise location of surrounding utilities and existing Metrolinx infrastructure.
- After reviewing the work plans and schedules, a suitable work window and track oversight are secured to ensure the work doesn’t interfere with regular train traffic.
- For overhead utility relocations, new poles are installed to raise the wires outside of the envelope of the proposed future infrastructure.
- For underground utility relocations, the sending and receiving pits are excavated outside of the corridors; conduits/ducts are tunnelled using various methods, including jack and bore, pipe ramming and micro-tunneling.
- Existing utilities are removed once the new infrastructure is strung overhead or pulled through conduits/ducts.
- Some works require temporary utility service shutdowns and/or temporary network diversions to minimize utility service interruptions.
Because utility companies know their infrastructure and network requirements better than anybody else, they actually lead their own relocation designs. They also use their own specialized contactors who have experience with working inside live rail corridors to perform the work.
Metrolinx coordinates among them, oversees rail corridor access and advances the schedules as much as possible by assisting with third party approvals as required – municipal, Ministry of Transportation (if highways are involved), park authorities, property access agreements, and so on
“We have also been working very hard on cutting down our own internal processes to move the utilities early works program forward as quickly as possible,” Lashley continued.
“We have been able to get our own approval timeline from about one year down to roughly three months with things such as design reviews and accounting for our existing railway infrastructure in them, planning rail corridor access and proper track oversight during construction.”
This is all very complex work, both in terms of design and construction. Every relocated utility has to connect back to a complex utility network, every relocation project requires a backup plan to ensure minimal service impacts and sometimes relocations even require network reconfigurations a few streets away from the actual rail corridor.
At the same time, every relocation has to meet its own industry’s current standards, and all of this work has to fit into and be captured in crossing agreements we maintain with each utility company.
“For me, it was a while back during (light rail transit) LRT tunneling work that I was first exposed to utility relocations, and from there it has slowly become not just a job, but a career path,” Lashley said. “My current role allows me to combine my knowledge of utility coordination with program management, and to continue building very positive and long-lasting relationships with some of our utility partners.”
As she works to untangle this particular web of wires and connections, Lashley knows that the work done today helps pave the way for future transit expansion across the entire region.
Much of this, residents and GO customers will never notice, but it’s important work as systems grow and have to occupy busy spaces.
Story by: Robert Pasiak, Metrolinx communications senior advisor