Yonge Relief Network Study
Metrolinx conducted the Yonge Relief Network Study (YRNS), in cooperation with the City of Toronto, TTC and York Region, in order understand the crowding on the TTC’s Line 1 Subway and develop options to address it.
The study found that planned and funded projects, such as Regional Express Rail (RER) and Automatic Train Control on Line 1 will significantly reduce crowding on the subway and help accommodate new growth until around the year 2031. However, as growth continues past 2031, a new transit project that can relieve demand on Line 1 will be required in order to maintain the resiliency and effectiveness of a transit network that can continue to support growth.
The study reviewed short, medium, and long term options, developed from a long list of over 150 project concepts. No individual short or medium term option could address long term crowding, however it was found that a combination of the options may delay the need for a major new infrastructure investment.
Long term options, including a surface LRT, four subway configurations, and improvements to RER were developed and tested using the Metrolinx four-chapter business case framework. This analysis concluded that the current transit expansion program will significantly shift demand from Line 1 but that further improvements to the northern GO lines will likely offer little additional relief to Line 1. The LRT option, despite being lower cost, was found not to have significant crowding reduction potential. It was determined that a new subway option, which may be tunnelled or use surface running alignments/legacy infrastructure, would be the most effective solution for long term Line 1 crowding.