1878 in rail transport

January events

 * January 18 – Construction on the Central Australia Railway route south of Port Augusta, Australia, begins.

February events

 * February 5 – The first train is operated on the Seattle & Walla Walla Railroad from Renton to Newcastle.

May events

 * May 9 – The final segment of the Romanian railway between Vârciorova in the south and Roman in the north opens.
 * May – Chemins de fer de l'État formed in France to take over ten small railway companies operating between the Loire and Garonne.

June events

 * June 1 – The North British Railway's Tay Bridge across the Firth of Tay in Scotland, is opened to public traffic, making it the longest in the world at that date.

July events

 * July 2 – The Brooklyn, Flatbush & Coney Island Railway, original predecessor of the BMT Brighton Line, in modern Brooklyn, New York, opens to Brighton Beach on Coney Island.

August events

 * August 24 – The narrow gauge Ballymena and Larne Railway starts passenger operations in County Antrim, the first on the Irish 3 ft narrow gauge.

October events

 * October 16 – Rimutaka Incline in New Zealand opens.

December events

 * December 4 – The first Shay locomotive is completed for the 3-foot narrow gauge Alleyton and Big Lake Railroad of Everett Township, Michigan.

Unknown date events

 * Fred Harvey enters a partnership with the Atchison, Topeka & Santa Fe Railway to build and operate the Harvey House chain of restaurants and hotels that will serve the railroad's passengers.
 * The Richmond & Danville Railroad acquires the Charlotte, Columbia & Augusta Railroad.
 * The Canadian Engine and Machinery Company is reorganized after a bankruptcy as the Canadian Locomotive and Engine Company.
 * The Wilmington, Columbia and Augusta Railroad, lessee of the Wilmington & Weldon Railroad, declares bankruptcy.

March births

 * March 2 – William Kissam Vanderbilt II, heir to Cornelius Vanderbilt and president of the New York Central system (d. 1944).

April births

 * April 14 – Angus Daniel McDonald, president of the Southern Pacific Company, parent company of the Southern Pacific, 1932–1941 (d. 1941).

March deaths

 * March 29 – Mark Hopkins, a member of The Big Four group of financiers in California (b. 1813).

June deaths

 * June 27 – Sidney Breese, U.S. senator from Illinois known as the "father of the Illinois Central Railroad," dies (b. 1800).

October deaths

 * October 19 – Benjamin Henry Latrobe, II, designer of Baltimore and Ohio Railroad's Thomas Viaduct, still in use toda), dies (b. 1806).

December deaths

 * December 27 – Daniel McCallum, General Superintendent of New York & Erie Railroad 1855–1858 (b. 1815).