The history of the Bala Subdivision is focused around the
Central Ontario port town of
Parry Sound. In the late 19th century, there were a number of plans to connect the Parry Sound area to the
Ottawa Valley (and from there, the
Saint Lawrence River) to the east,
Toronto in the south, and
James Bay in the north. After a number of disparate efforts in the 1880s by forces such as the
Canadian Northern Railway (CNoR), the former materialized as the
Ottawa, Arnprior and Parry Sound Railway, which bypassed the town to reach a western terminus at
Depot Harbour nearby, and connected to the
Northern and Pacific Junction Railway which ran from Toronto to
Nipissing Junction, where it connected to the
Canadian Pacific Railway line. With the increasing attractiveness of
Sudbury as a rail destination due to the mining boom in the
Sudbury Basin, the Canadian Northern's
James Bay Railway was rechartered as the
Canadian Northern Ontario Railway and rerouted through Sudbury. Construction was hindered as the company attempted to penetrate through Toronto's crowded railway network to Union Station in the south, and a small
railway battle occurred when the CNoR's construction crews attempted to build a level crossing with the Grand Trunk Railway tracks at
Rosedale. The GTR, in preparation for this, had blocked their path with a freight car, which was destroyed by the CNoR crews with dynamite. Ultimately the two railway companies came to an agreement to terminate the CNoR line at a junction (Rosedale Junction) with the GTR-owned and largely-defunct
Toronto Belt Line Railway, and for CNoR trains to use the Belt Line to reach Union Station. The Toronto–Parry Sound segment was completed in 1906, terminating in the south at Rosedale Junction, running northward to the east of
Lake Simcoe before crossing over the former
Northern Railway of Canada (NRC) line to North Bay, which would later become known as the
CN Newmarket Subdivision. At the time, this new line was known as the Parry Sound Section of the Canadian Northern, but by 1914 it was being referred to as the Parry Sound Subdivision of the Toronto Division, and later the Muskoka Subdivision of the Nipissing Division. This would soon change, however, as CN's operations around Toronto were significantly reorganized in the 1960s. CN had made far-reaching plans to relocate much of its freight operations to the north end of Toronto, centred on a new freight yard the
MacMillan Yard, and to abandon the century-old waterfront yard in the downtown
Railway Lands, freeing that land up for redevelopment. This would be accomplished with a new east–west line, the
CN York Subdivision, which would intersect with the Bala Subdivision just south of Richmond Hill at
Doncaster Junction. Both were completed in 1965. A
GO Transit Richmond Hill line was initially proposed in 1969, but the proposal was scrapped in 1970 in favour of a bus service. The Richmond Hill line would ultimately only begin service in 1978, almost a decade after it was proposed. Around this time, CN divested itself of its passenger services, which were handed over to a new
Crown corporation,
Via Rail, whose services continued to follow the Newmarket Subdivision rather than the Bala Subdivision south of Washago. Even with the resumption of passenger services along the southern part of the line with the GO Richmond Hill line, the line "suffered from neglect," In 2005, CN and CP negotiated the creation of a
directional running zone utilizing both of their lines. Starting at mile 146 (Boyne) just south of Parry Sound, all northbound trains began using the
CP Parry Sound Subdivision, while southbound trains, including Via passenger and CP freight trains, began using the Bala Subdivision exclusively. The long-closed CP passenger station was reactivated, creating an unusual situation where the unified Via passenger services used both of the historic CN and CP stations in a single community. As of 2019, the Via Rail
Canadian continues to use the CP station for northbound trains and the CN station for southbound ones. Starting in the early 2010s,
Metrolinx, the provincial
Crown agency which oversees
GO Transit operations, began to invest more heavily in the line. A significant milestone in this was the inclusion of the segment of the line from Rosedale Valley Road north through the Don Valley to Doncaster Junction in a CA$310.5 million combined purchase of track from CN in 2012, which also included a portion of the
Oakville Subdivision. In 2016, for the first time since the launch of GO train service along the line, regular GO Transit revenue service was extended north of
Richmond Hill station to
a new station at Gormley, complementing a new train depot which had been constructed in 2014. This was followed by plans for a
Bloomington station, construction on which began in 2017. ==Operations==