The Lancashire and Yorkshire Railway (L&YR) was a major British railway company incorporated in 1847 from an amalgamation of several existing railways. It owned 1,650 locomotives – it was apparently the most densely trafficked system in the British Isles with more locomotives per mile than any other company. No two adjacent stations were more than 5.5 miles (9 km) apart. It was the first mainline railway to introduce electrification of some of its lines, and it also ran steamboat services across the Irish Sea and North Sea.
It amalgamated with the London and North Western Railway on 1 January 1922. One year later, the merged company became the largest constituent of the London, Midland and Scottish Railway.