George Augustus Nokes 
The evolution of the steam locomotive [EPUB ebook] 

In connection with the marvellous growth of our railway system there is nothing of so paramount importance and interest as the evolution of the locomotive steam engine.
At the present time it is most important to place on record the actual facts, seeing that attempts have been made to disprove the correctness of the known and accepted details relative to several interesting, we might almost write historical, locomotives.
In this work most diligent endeavours have been made to chronicle only such statements as are actually correct, without reference to personal opinions.
In a broad sense, and taken as a whole, the old works on locomotive history may be accepted as substantially correct.
From these, therefore, and from authentic documents provided by the various railways, locomotive builders, and designers, together with the result of much original research, has the earlier portion of this account of the evolution of the locomotive steam engine been constructed. The various particulars of modern locomotive practice have been kindly supplied by the locomotive superintendents of the different British railways, so that no question can arise as to the strict accuracy of this portion of the work.