The Lancashire & Yorkshire Railway Company (L&YR) was a major British railway company and was formed in July 1847 from an amalgamation of the following three companies:
The Manchester & Leeds Railway had previously acquired the Huddersfield & Sheffield Junction Railway in July 1846, which was a new line linking Penistone to Huddersfield.
Around the same time as the L&YR was formed, the rival London & North Western Railway Company (L&NWR) had acquired the Huddersfield & Manchester Railway & Canal Company (then under construction) which would provide them with a more direct link between Manchester and Leeds than the L&YR's earlier route though the Upper Calder Valley. However, the L&YR's ownership of the former Ashton, Stalybridge & Liverpool Junction Railway meant that they had control over the Huddersfield & Manchester Railway route between Manchester and Stalybridge.
As a further complication, through an earlier Act of Parliament that had gained Royal Ascent in July 1846, the two companies that had been building lines to Huddersfield had agreed to share ownership of Huddersfield Railway Station as well as the section of railway from Springwood Junction to the station. However, even with that agreement in place, the L&YR's Penistone to Huddersfield line would suffer from being physically unconnected to the rest of the company's network.
Under the circumstances, the L&NWR and L&YR both gained from mutual cooperation and various arrangements relating to running powers over each others' lines were agreed upon, including: