W. Worsdell, who designed No. 1518 (built at Gateshead works) , was an enthusiast for compounding and many of his designs used the two-cylinder system of August von Borries, usually in conjunction with simple-expansion versions of the same engines for comparison. The compounds were mostly rebuilt as simple-expansion engines by his brother and successor Wilson Worsdell. August Friedrich Wilhelm von Borries (1852 –1906) was one of Germany’s most influential railway engineers concerned with developments in steam locomotives. Worsdell introduced the system of class designations, starting with “A” for the first, and so on, and then adding a digit for later developments of each. This system was reorganised somewhat in 1914.
The North Eastern Railway was formed by merger in 1854 and merged into the London and North Eastern Railway at the grouping in 1923. Between those dates five men held the post of Locomotive Superintendent.