1846 in rail transport

File:Hugh llewelyn 3 (5384898364).jpg, entered service February 1846 in the north of England]]

• January 9 – Barentin Viaduct on the Paris–Le Havre railway collapses soon after its completion by English engineers.{{cite book|last=Walker|first=Charles|title=Thomas Brassey, Railway Builder|publisher=Muller|year=1969|location=London|pages=48–9|isbn=0-584-10305-0}}
• January 13 – Opening of the Milan–Venice railway's {{convert|3.2|km|mi|abbr=on}} bridge over the Venetian Lagoon between Mestre and Venice in Italy.{{cite web|url=http://en.structurae.de/structures/data/index.cfm?id=s0007311|title=Venice Railroad Bridge|work=Structurae|accessdate=2011-06-17}}{{cite book|title=Italian Railways|first=P. M.|last=Kalla-Bishop|year=1971|publisher=David & Charles|location=Newton Abbot|isbn=0-7153-5168-0|page=20}}

• March 26 – John M. Forbes becomes president of the Michigan Central Railroad.{{cite web|url=http://oprt.org/history/timeline.html|title=Timeline of Old Plank Road Trail history and development|accessdate=2005-03-01|archiveurl=https://web.archive.org/web/20050214161136/http://oprt.org/history/timeline.html|archivedate=2005-02-14|url-status=dead}}

• June 14 – The first Gare du Nord station in Paris, France, is opened.
• June 20 – The Paris–Lille railway is opened in France.
• June 22 – The North British Railway is opened to public traffic between Edinburgh and Berwick-upon-Tweed, the first line to cross the border between Scotland and England. Waverley Station is opened.{{cite book|last=Thomas|first=John|title=The North British Railway, vol. 1|year=1969|publisher=David & Charles|location=Newton Abbot|isbn=0-7153-4697-0}}
• June 26 – The Great Northern Railway (Great Britain) is authorised by Act of Parliament with powers to construct a direct line from London to York with a loop via Boston, {{convert|233.5|mi|km|abbr=on}} with a capital of £5,600,000, the largest single scheme ever approved by Parliament.{{Marshall-GuinnessRail}}{{page needed|date=October 2016}}

• July 1 – The Leeds and Bradford Railway opens between Leeds and Bradford, West Yorkshire, England.
• July 15 – The first railway line in Hungary opens between Pest and Vác.
• July 16 – The London and North Western Railway is formed in England by amalgamation of the London and Birmingham Railway, Grand Junction Railway and Manchester and Birmingham Railway.{{cite book|author=Reed, M. C.|title=The London & North Western Railway: a history|year=1996|publisher=Atlantic|location=Penryn|isbn=0-906899-66-4}}

• August 11 – First section of Furness Railway in England opens to mineral traffic; passengers are first carried on December 1.{{cite web|url=https://spellerweb.net/rhindex/UKRH/OtherRailways/FurnessRailway.html|title=Furness Railway|work=John Speller's Web Pages - Other Railways|accessdate=2020-05-01}}
• August 18 – Gauge Act passed by the Parliament of the United Kingdom{{cite web|url=http://www.railwaysarchive.co.uk/docSummary.php?docID=60 |title=Railway Archive |accessdate=7 July 2007 |archiveurl=https://web.archive.org/web/20070820043850/http://www.railwaysarchive.co.uk/docSummary.php?docID=60 |archivedate=20 August 2007 |url-status=dead }} rules that new railways in Great Britain should be built to standard gauge and 5 ft 3 inches in Ireland unless otherwise authorised.
• August 28 – Railway Mania reaches its zenith as the Parliament of the United Kingdom closes its session having passed 272 Acts setting up new railway companies.{{cite book|author=Lewin, Henry Grote|title=The Railway Mania and its aftermath, 1845–1852|year=1936|publisher=Railway Gazette|location=London}}

• September 21 – The town of Kendal, England, declares a public holiday for the opening of the Kendal, Oxenholme and Lancaster section of the Lancaster and Carlisle Railway; the first revenue trains are operated on September 22.{{cite web|url=http://home.clara.net/gw0hqd/past/|author=Friends of Carnforth Station|title=The History Of Carnforth Railway Station (and surrounding area)|accessdate=2005-09-21|archive-url=https://web.archive.org/web/20041116091241/http://home.clara.net/gw0hqd/past/|archive-date=2004-11-16|url-status=dead}}
• September 28 – The East Lancashire Railway opens to the public from Clifton Junction to Rawtenstall in England.

• November 10 – Portland Company established by John A. Poor and Septimus Norris of the Norris Locomotive Works.{{cite book|title=The Grand Trunk in New England|author=Holt, Jeff|publisher=Railfare|year=1985|isbn=0-919130-43-7|page=124}}

• December 17 – The Lancaster and Carlisle Railway is opened throughout to Carlisle.

• April 13 – Lucius E. Johnson, president of the Norfolk and Western Railroad 1904–1921 (d. 1921).

• October 6 – George Westinghouse, American inventor; developed the Westinghouse air brake (d. 1914).