3.2K 
Yesterday, Metrolinx officially announced that two-way all-day (commonly abbreviated as 2WAD) GO Train service will be coming to the Stouffville GO line, commencing on Monday, June 26th. The train trips will run approximately every hour in both directions, between Unionville GO and Union Station, with select peak trips continuing to run to/from Lincolnville GO, the current terminus of the line. This service increase adds 17 new trips to the line per weekday, bringing the total trips on the line per week from 85 to 170.
This will make the Stouffville Line the fourth GO Train line, after Lakeshore East, Lakeshore West, and Kitchener, to be classified as 2WAD service. However, unlike the Lakeshore corridor, counter-flow service (service originating from Union in the AM peak and Unionville in the PM peak) will continue to be provided by buses, as the necessary track infrastructure to permit this type of service during peak periods is not yet in place.
No train service will operate on weekends, still leaving the Lakeshore corridor as the only lines on which weekend trains run hourly or better. The Barrie Line does have weekend service, though not 2WAD (3 trips inbound from Barrie and 7 from Aurora, and 3 outbound to Barrie and 6 to Aurora), and Niagara Falls sees seasonal weekend trips.
The first Unionville-bound train in the morning is at 10:15, after the morning rush hour has concluded. In the PM, there is a gap in Union-bound service from Unionville of over 5 hours, with the last mid-day train departing at 15:46 and the next one not departing until 21:01, so office workers in Markham's business area who live in Downtown Toronto will still be out of luck when it comes to a GO Train trip home. The Kitchener Line has a similar setup, where trains operate in both directions during mid-day, but the line currently lacks counter-flow trips during peak periods. While Metrolinx classifies both of these lines as 2WAD, during the periods that matter most they still effectively function as uni-directional commuter lines.
As was detailed in previous articles on the Lakeshore East and Barrie corridors, Metrolinx is undertaking a sizeable amount of work in preparation for the implementation of Regional Express Rail (RER). Under the plan, the Stouffville corridor will be double-tracked from Scarborough Junction (where it meets the Lakeshore East corridor) to Unionville, approximately 17 km, and the entire corridor will be electrified. This will permit 2WAD service every 15 minutes or better between Union and Unionville, 2WAD service every 60 minutes or better between Union and Mount Joy, and peak direction service every 20 minutes or better between Union and Lincolnville.
Double tracking work on a 5 km section of the line, from Kennedy Rd in Markham to just north of Sheppard Ave E, will be completed by the end of this year. This represents the first phase of a multi-phase effort to double track the entire 17 km stretch. When each phase is completed, it will allow GO greater operational flexibility in terms of train frequency and scheduling. Currently, the frequency of trains is largely limited by the presence of passing tracks along the corridor, which limits it to hourly bi-directional service. These phases will incrementally allow for increased frequency, until the promised 15 minute frequencies are possible.
In addition to track upgrades, Metrolinx is also in the process of tendering station upgrade contracts. Request for Proposals (RFPs) are currently out for improvements to Unionville, Milliken, and Agincourt stations. Based on the RFP, posted in September 2016, a successful bidder is due to be announced in "Spring 2017". Improvements to Kennedy GO are being undertaken as part of the Crosstown LRT project, and thus were not included in this tender package.
With the gradual expansion of the Stouffville corridor to be completed between now and 2020, we are sure to see several incremental service improvements announced in the coming years. UrbanToronto will keep you up to date on any future improvements made on the road to RER. You can join the discussion by visiting our forum page, or by leaving a comment below.
Correction: An earlier version of the article stated that weekend service on the Barrie Line was seasonal. In fact, year-round weekend service began on the Barrie Line on December 31, 2016.
