In the aftermath of the Great War the government decided to forcibly amalgamate the more than sixty railway companies into four groups from 1st January 1923; these became the 'Big Four', the LMS, LNER, GWR and Southern.

In an attempt to dominate the LMS group, the Lancashire & Yorkshire Railway and the London & North Western Railway amalgamated on 1st January 1922 with the L&Y General Manager and Chief Mechanical Engineer taking those roles in the new larger company. 

This profusely illustrated booklet describes the process using material from the period and shows how these two great companies started to combine their operations and equipment. It is a short but fascinating period of railway history which quickly became subsumed in the in-fighting of the early LMS period, but well worth knowing more about.