The railway ran tip-to-tip on the island, from Tignish in the west to Elmira in the east, with major spurs serving Borden-Carleton's train ferry dock, the capital in Charlottetown, Montague and Georgetown and the original eastern terminus at Souris.

The line officially closed on 31 December 1989 and the rails removed between 1990 and 1992, with the provincial government receiving a one-time payment of $200 million to upgrade the road network in exchange for not opposing the closure.

Located wholly within the province of Prince Edward Island, construction of the PEIR started in 1871, eventually financed by Canada.

The PEIR was frequently criticized for its meandering path, reputedly caused by construction contractors who were paid by the mile; this may also be accounted for in economies taken by reducing the amount of grading and trenching required by going around hills and obstacles.

The United Kingdom had consistently encouraged the small colony to enter into Canadian Confederation, something which it had been avoiding since playing host to the Charlottetown Conference a decade earlier.

The railway construction debts pushed the colony into reconsidering Confederation, and following further negotiations, Prince Edward Island became a province of Canada on July 1, 1873.

From 1915 to 1918, PEIR and IRC would come to be known collectively as the Canadian Government Railways (CGR), although each company would maintain its separate corporate identity and management.

In the meantime, the Prince Edward Island continued to operate the service to the port of Pictou, Nova Scotia from Georgetown and Charlottetown for the next two years.

In September 1918, management of CGR (including PEIR) was transferred to the newly nationalized Canadian Northern Railway (CNoR).

These companies were assumed by a new Crown corporation established by the federal government in December 1918, called Canadian National Railways (CNR).

In 1951, the Hillsborough River bridge was deemed too weak to carry even the lightest engines and cars, thus the trackage was removed and trains trying to reach Southport on the opposite side of Charlottetown Harbour would have to run over 30 miles (48.3 km) via Mount Stewart Junction and the Short Line.

The ferry system was noteworthy by the fact that it was mandated by Prince Edward Island's "Terms of Union" under the British North America Act of Canadian Confederation, to provide "efficient steamship service."

Trucks soon began to take traffic away from freight operations on Prince Edward Island, particularly as CNR improved the ferry system to accept more road vehicles.

[2] In 1990, a diesel locomotive (class MLW RSC-14 number 1767) donated to Summerside several years earlier, needed to be moved to nearby Kensington.

The locomotive was towed by construction machinery across temporary tracks built over these roads to its new location, where it remains on display as part of a community-operated railway museum.

The line to Northport was turned into a spur by building a large wye junction at the sharp curve that developed when the extension was added.

The mainline continues out of Mount Stewart and passes through Morell, and, on the eastern side of town, begins to parallel the northern coast of the island as far as Saint Peter's Bay.

Here it leaves the coast and continues eastward to a wye at Harmony Junction, where it originally looped back westward and then south for the short run to Souris.

The Harmony wye made the Souris line a spur, with the mainline continuing east to its ultimate end in Elmira.

The Murray Harbour Line started at the end of the mainline spur in Charlottetown, crossing the Hillsborough River Bridge (the original pilings can still be seen) before bending sharply to the northeast through Bunbury.

Steven Boyko notes on his blog[6]Side note: RDC D302 was tested on PEI in March 1958 but "it proved unsuitable because of difficulties it encountered crossing the ferry ramp, and negotiating the sharp turns between Borden and Charlottetown".The following vessels were owned and operated by CNR/CN (1918–1977), CN Marine (CN subsidiary, 1977–1986) or by successor Marine Atlantic (post-1986) on the Northumberland Strait ferry service: * denotes combination train ferry/ferry