1903 in rail transport

January events

 * January 20 – The Grand Trunk Western Railroad opens a passenger depot in Lansing, Michigan.
 * January 28 – Esmond Train Wreck: fourteen people are killed when the Crescent City Express (No. 8, bound for Benson, Arizona) collides head-on with the bound Pacific Coast Express (No. 7, bound for Tucson).

February events

 * February 12 – North British Locomotive Company established as a locomotive builder in Glasgow, Scotland, by merger of Dübs & Company, Neilson, Reid & Company, and Sharp, Stewart & Company. In April it receives its first new order for steam locomotives, from India.

March events

 * March 3 – Baker valve gear for steam locomotives is first patented in the United States.

April events

 * April 7 – Apalachicola Northern Railroad, later to become AN Railway, is chartered.

May events

 * May 3 – The Mersey Railway, operating between Birkenhead and Liverpool by tunnel beneath the River Mersey, England, converts from steam to electric traction.
 * May 13 – The Fremont, Elkhorn & Missouri Valley Railroad (later to become part of Chicago & North Western Railway) begins passenger train service to Casper, Wyoming.
 * May 25 – The Lackawanna & Wyoming Valley Railroad opens, becoming the first railroad in the United States to use an electrified third rail to power its trains.

July events

 * July – Regular passenger traffic from Saint Petersburg to Vladivostok over the Trans-Siberian and Chinese Eastern Railways begins.
 * July 1 – Opening of the Albula Railway portion of the Rhaetian Railway (RhB) (metre gauge) in Switzerland, passing through the Albula Tunnel, the highest of the principal Alpine tunnels at 1370 m.
 * July 13 – Danbury Union Station in Danbury, Connecticut, on the New York, New Haven & Hartford Railroad, opens.
 * July 27
 * Construction begins on the Baghdad Railway with the 200 km segment between Konya and Bulgurlu in the Ottoman Empire (modern day Turkey).
 * Glasgow St Enoch rail accident, Scotland: sixteen killed when a train crashes into the buffers.

August events

 * August 10 – Paris Metro train fire, France: electric fire on Paris Métro at Couronnes; 84 killed.
 * August 17 – The Great Western Railway becomes the first British railway company to operate its own road motor services (i.e. buses), between Helston and The Lizard in Cornwall.

September events

 * September 27 – Wreck of the Old 97, Danville, Virginia, United States: A southbound Southern Railway passenger train derails on a trestle in Danville; eleven people are killed.

October events

 * October – Experimental electric trains, built by AEG and Siemens & Halske, reach 210.2 km/h (130.6 mph) between Marienfelde and Zossen in Germany.
 * October 1
 * The first railway in Norway rebuilt to double track, from Bryn to Lillestrøm on the Hovedbanen, is opened.
 * The Gold Coast Government Railway is extended from Obuasi to Kumasi.
 * October 21 – Howard Elliott succeeds Charles Sanger Mellen as president of Northern Pacific Railway.
 * October 26 – The Key System begins operating their first streetcar-ferry service, the Berkeley line in Berkeley, California.
 * October 31 – The Purdue Wreck, Indianapolis, Indiana, USA: A Cleveland, Cincinnati, Chicago & St Louis Railway football special carrying the Purdue University football team and fans to the annual game with Indiana University collides with a coal train. Fourteen of the team and three other passengers are killed.

November events

 * November 9 – The gauge Kalka-Shimla Railway opens in India.

December events

 * December 14 – The New York, New Haven and Hartford introduces the all-parlor car Merchants Limited between Boston and New York City.

Unknown date events

 * The British Engineering Standards Committee draws up specifications for eight standard steam locomotive designs for the broad gauge Indian Railways.
 * Southern Pacific Railroad gains 50% control of the Pacific Electric system in Los Angeles, California.
 * The Wilkes-Barre & Hazleton Railway opens as the first railroad to have a guarded third rail.
 * The provisions of the Railroad Safety Appliance Act, enacted in 1893, are extended to include all railroad cars whether or not the cars themselves are used in interchange service.
 * Atchison, Topeka & Santa Fe Railway introduces the first 2-10-2 compound locomotives (built by Baldwin Locomotive Works) into service.
 * Edward Harriman becomes president of the Union Pacific.
 * George Whale succeeds Francis William Webb as Chief Mechanical Engineer of the London & North Western Railway.

April births

 * April 10 – Edward T. Reidy, last president of Chicago Great Western Railway 1957–1968.

March deaths

 * March 29 – Gustavus Franklin Swift, founder of Swift & Company which pioneered the use of refrigerator cars in late 19th century America (born 1839)

July deaths

 * July 27 – Frederick Kimball, American civil engineer who was instrumental in the formation of Norfolk & Western (born 1844).

Unknown date deaths

 * John Elfreth Watkins, railroad civil engineer and first curator for the Smithsonian Institution's railroad artifacts including John Bull.