In July 2014, GO Transit released its environmental study on rail service expansion in the Stouffville corridor. The report proposes incremental twinning of the tracks between Mount Joy and Kennedy GO Stations in order to run full GO Train service.
There is a lot of detailed engineering design that remains to be completed such as full road/rail grade separations, installation of noise barriers and the construction of retaining walls. For more information you can read the environmental study at http://tinyurl.com/m7op9bk.
In February, Metrolinx announced that they will build a second set of tracks on a 5 km stretch of the Stouffville corridor from north of Steeles to north of Sheppard. Construction is set to start this spring. Double-tracking the rest of the line will follow and is critical to Mayor Tory’s SmartTrack plan.