The Newfoundland Railway was a narrow-gauge railway that operated on the island of Newfoundland from 1898 to 1988. With a total track length of 906 miles (1,458 km), it was the longest 3 ft 6 in (1,067 mm) narrow-gauge system in North America.

In 1880, a committee of the Newfoundland Legislature recommended that a narrow-gauge railway be built from the colonial capital in St. John's to Halls Bay, 547 km (340 mi) to the west. Construction was started on the Avalon Peninsula in August 1881 by the Blackman Syndicate. By 1884, the Newfoundland Railway Company had built 92 km (57 mi) west to Whitbourne before going into receivership.

The bondholders of the bankrupt Newfoundland Railway Company continued to build a 43 km (27 mi) branch line from Brigus Junction to Harbour Grace (the Harbour Grace Railway), which was completed by November that year.

The colonial government undertook to build a branch from the junction at Whitbourne to the port of Placentia between 1886 and 1888.

The colonial government sought new investors to continue the stalled project to Halls Bay and in June 1890, Scottish-born Montreal resident and railway engineer/contractor Robert Gillespie Reid agreed to build and operate the line. By 1892, Reid's workers were approaching the halfway point at the Exploits River when the government changed the terminus from Halls Bay approximately 400 km (250 mi) further west, first to St. George's and finally to Port aux Basques. The route itself was diverted inland up the Exploits valley and over the Gaff Topsails (some of the highest elevation terrain on the island) and away from the coast once on the north bank of the Exploits River. This extension to the system was initially operated as the Newfoundland Northern and Western Railway and for it, Reid was granted land totalling 5,000 acres per mile (13 km²/km).

The new line west to Port aux Basques was completed between 1894 and 1898. At the same time, Reid proposed a ferry service across the Cabot Strait from Port aux Basques to North Sydney, Nova Scotia, and contracted for a steamship to be built in Scotland. The Bruce arrived in the fall of 1897, before the line was completed to Port aux Basques, so her initial runs to Cape Breton Island were made from Little Placentia Sound. On June 29, 1898, the first passenger train arrived at Port aux Basques and the Bruce set sail with passengers for North Sydney.

Later that year, the colonial government persuaded Reid's company to take over operation of the bankrupt Newfoundland Railway Company and its sister Harbour Grace Railway, as well as the government-owned Placentia branch, in order to unify the system across the entire island (known as the Railway Contract of '98). The Reid company agreed to operate the lines for 50 years, in exchange for outright ownership and land grants. They also purchased the government drydock in St. John's and the telegraph system. The Reid company purchased eight new steamships to operate as coastal ferries around the island and into Labrador.

Controversy followed the awarding of so many assets to Reid, and in 1901 the contracts were modified to place everything under a limited liability corporation, named the Reid Newfoundland Company.