The Drafting of Steam Locomotives

Abstract

Abstract The paper gives a chronological summary of the experiments with and developments of various appliances for obtaining the draft necessary for firing steam locomotives. For the more important of these, test results are given and the advantages and defects are pointed out. This part of the paper concludes with a listing in the order of merit of five of the principal draft devices as tested by the author. There follows a discussion of the characteristics and limitations of the relationship between exhaust pressure and draft, in the double-engine reciprocating steam locomotive having a single constant-area exhaust nozzle and intercommunicating exhaust passages. The paper concludes by pointing out how the present standard exhaust nozzles limit the economic working range of locomotives, and suggesting changes in design to give better efficiency and a greater economic working range.