This system of manufacture, together with the large number of locomotives at all times in progress, and embracing the principal classes, insures unusual and especial facilities for filling at once, or with the least possible delay, orders for duplicate parts. Full specifications of locomotives will be furnished on application. M. BAIRD & CO. EXPLANATION OF TERMS. The several classes of locomotives manufactured by the Baldwin Locomotive Works have their respective distinguishing names, which are derived and applied as follows: All locomotives having one pair of driving-wheels are designated as B engines. Those having two pairs of drivers, as C engines. Those having three pairs of drivers, as D engines. Those having four pairs of drivers, as E engines. One or more figures united with one of these letters, B, C, D, or E, and preceding it, indicates the dimensions of cylinders, boiler, and other parts, and also the general plan of the locomotive: thus, 27-1/2 C designates the class of eight-wheeled locomotives (illustrated on pages 56 and 60) with two pairs of drivers and a four-wheeled truck, and with cylinders sixteen inches in diameter and twenty-two or twenty-four inches stroke. 34 E designates another class (illustrated on page 80), with four pairs of drivers and a pony truck, and with cylinders twenty inches in diameter and twenty-four inches stroke. In like manner all the other classes are designated by a combination of certain letters and figures. All corresponding important parts of locomotives of the same class are made interchangeable and exact duplicates. The following table gives a summary of the principal classes of locomotives of our manufacture: GENERAL CLASSIFICATION.