In the 1860s, established railway companies were replacing their small 2-2-0 and 0-4-0 steam locomotives with larger, more modern machines.
Mr I. W. Boulton took advantage of this by buying up some of the old locomotives, modifying them in his workshop, and hiring them out to contractors for use on civil engineering projects, including the building of new railways.
He used his own patent design of boiler which had a single large flue with cross water-tubes.
This was, essentially, a horizontal predecessor of the vertical water-tube boilers later used in Sentinel Steam Waggons.
This book was founded on a series of articles contributed by the author to the Locomotive Magazine between November, 1920, and February, 1925.