Ottawa’s Light Rail Transit (LRT) system is facing recurrent challenges due to intense electric flashes causing wire breakages and rekindling memories of past train service disruptions. OC Transpo has attributed these issues to freezing rain, prompting transit authorities to question why previously effective solutions suddenly failed on three separate occasions last week.
The LRT’s overhead catenary system, which utilizes suspended wires to supply electric power to the trains, is experiencing wire fractures. OC Transpo employees observed “arcing” on trains between Hurdman and Lees stations just before the initial break was detected. Arcing, captured on camera by a bystander, involves sparks emanating from the pantograph of a train, the device on its roof designed to connect with the wire.
Arcing is a phenomenon where electric current surges through the air between two conductive surfaces. This occurs when the pantograph loses contact with the wire, creating a gap for the current to jump across. Mohamed Youssef, an electrical engineering professor at Ontario Tech University with rail industry experience, likens this process to lightning, with the wire acting as the cloud and the pantograph as the ground.
OC Transpo’s acting general manager, Troy Charter, attributes the recent issues to ice accumulation, creating an uneven surface that heightens the likelihood of arcing incidents. Extreme arcing led to two failures on a Friday, including a broken wire near Blair Station and another problem near Tremblay Station involving a sagging wire, described as a “burr.”
Despite ice removal efforts along the line, residual ice melting on the overhead catenary system may have contributed to the subsequent issues. OC Transpo’s response, including running trains more frequently to prevent ice buildup and applying glycol treatments to the wires, has not prevented the recent disruptions. In light of these challenges, OC Transpo is exploring a “heat tracing” system as a potential long-term solution to prevent ice formation and bolster system resilience, although the feasibility and costs of such a system are under consideration.