While blasting the route through the shield, geologists discovered deposits of valuable minerals such as gold, silver, copper and nickel.

There is one major branchline running eastward from Swastika through Kirkland Lake and over the Quebec border to end at Rouyn-Noranda.

Since 1993, the ONR operates a section of the National Transcontinental Railway running west from Cochrane to Calstock.

As it passed by Long Lake, near the 103 mile marker, the largest silver rush in Canada was sparked by workers looking for trees for railway ties.

CN submitted a bid in March 2002, and in October the government gave it exclusive rights to negotiate a purchase of the railway.

However, the deal fell through on July 2, 2003, over the government's insistence on job guarantees, and the railway remained in public hands.

On April 14, 2010, there was news of a proposed Ontario Northland takeover of the controversial Ottawa Valley rail tracks.

[6] On August 16, the Ontario Government announced that Northlander train service would end on September 28, 2012, and Ontera will be sold off.

They indicated that the ONR provides a fundamental link to many remote and rural communities and provides freight transport to many companies, including mining and forestry, allowing them to thrive.

[9] In late February 2014 a report to restructure the ONTC was delivered to the Minister of Northern Development and Mines.

The government would reinvest in the company to purchase new coaches and refurbish rolling stock for the Polar Bear Express.

In November 2021, the decision was made to make the new terminus Timmins (previously Cochrane) due to its size and the fact that it serves as a regional transportation hub.

[14][15] A test run was conducted in March 2021, and again in November of 2021 where several northern Ontario mayors, MPPs, and local residents were taken from North Bay to Toronto's Union station.

[16] In December 2022, the provincial government announced that it would purchase 3 new train sets from Siemens Mobility Limited at a cost of $140 million.

There would be 16 stops: Toronto (Union Station), Langstaff, Gormley, Washago, Gravenhurst, Bracebridge, Huntsville, South River, North Bay, Temagami, Temiskaming Shores, Englehart, Kirkland Lake/Swastika, Matheson, Timmins and Cochrane.

In April 2022 the Ontario Government announced that it would invest $75-million (CAD), into infrastructure and towards resuming service between Toronto and Timmins.

One of its more unusual pieces of rolling stock is a canoe car, which is in service in the summer as part of the Polar Bear Express passenger train.