In 1867, on a number of eight-wheeled four-coupled engines, for the Pennsylvania Railroad, the four-wheeled swing-bolster-truck was first applied, and thereafter nearly all the engines built in the establishment with a two- or four-wheeled truck in front have been so constructed. The two-wheeled or "pony" truck has been built both on the Bissell plan, with double inclined slides, and with the ordinary swing-bolster, and in both cases with the radius-bar pivoting from a point about four feet back from the centre of the truck. The four-wheeled truck has been made with swing-bolster exclusively and without the radius-bar. Of the engines above referred to as the first on which the swing-bolster-truck was applied, four were for express passenger service, with drivers sixty-seven inches in diameter, and cylinders seventeen by twenty-four. One of them, placed on the road September 9, 1867, was in constant service until May 14, 1871, without ever being off its wheels for repairs, making a total mileage of one hundred and fifty-three thousand two hundred and eighty miles. All of these engines have their driving-wheels spread eight and one-half feet between centres, thus increasing the adhesive weight, and with the use of the swing-truck they have been found to work readily on the shortest curves on the road.
Steel flues were put in three ten-wheeled freight engines, numbers 211, 338, and 368, completed for the Pennsylvania Railroad in August, 1868, and up to the present time have been in constant use without requiring renewal. Flues of the same material have also been used in a number of engines for South American railroads. Experience with tubes of this metal, however, has not yet been sufficiently extended to show whether they give any advantages commensurate with their increased cost over iron.
Steel boilers have been built, to a considerable extent, for the Pennsylvania, Lehigh Valley, Central of New Jersey, and some other railroad companies, since 1868, and with good results thus far. Where this metal is used for boilers, the plates may be somewhat thinner than if of iron, but at the same time, as shown by careful tests, giving a greater tensile strength. The thoroughly homogeneous character of the steel boiler-plate made in this country recommends it strongly for the purpose.
In 1854, four engines for the Pennsylvania Railroad Company, the "Tiger," "Leopard," "Hornet," and "Wasp," were built with straight boilers and two domes each, and in 1866 this method of construction was revived. Since that date, the practice of the establishment has included both the wagon-top boiler with single dome, and the straight boiler with two domes. When the straight boiler is used, the waist is made about two inches larger in diameter than that of the wagon-top form. About equal space for water and steam is thus given in either case, and, as the number of flues is the same in both forms, more room for the circulation of water between the flues is afforded in the straight boiler, on account of its larger diameter, than in the wagon-top shape. The preference of many railroad officers for the straight boiler is based on the consideration of the greater strength which this form confessedly gives. The top and side lines being of equal length, the expansion is uniform throughout, and hence there is less liability to leak on the sides, at the junction of the waist and fire-box. The throttle-valve is placed in the forward dome, from which point drier steam can be drawn than from over the crown-sheet, where the most violent ebullitions in a boiler occur. For these reasons, as well as on account of its greater symmetry, the straight boiler with two domes is largely accepted as preferable to the wagon-top form.
Early in 1870, the success of the various narrow-gauge railway enterprises in Europe aroused a lively interest in the subject, and numerous similar lines were projected on this side of the Atlantic. Several classes of engines for working railroads of this character were designed and built, and are illustrated in full in Division VII of the Catalogue.
The history of the Baldwin Locomotive Works has thus been traced from its inception to the present time. Over twenty-six hundred locomotives have been built in the establishment since the completion of the "Old Ironsides," in 1832. Its capacity is now equal to the production of over four hundred locomotives annually, and it has attained the rank of the largest locomotive works in the world. It owes this position not only to the character of the work it has turned out, but largely also to the peculiar facilities for manufacture which it possesses. Situated close to the great iron and coal region of the country, the principal materials required for its work are readily available. It numbers among its managers and workmen men who have had the training of a lifetime in the various specialties of locomotive-manufacture, and whose experience has embraced the successive stages of American locomotive progress. Its location, in the largest manufacturing city of the country, is an advantage of no ordinary importance. In 1870, Philadelphia, with a total population of nearly seven hundred thousand souls, gave employment in its manufactures to over one hundred and twenty thousand persons. In other words, more than one-sixth of its population is concerned in production. The extent of territory covered by the city, embracing one hundred and twenty-seven square miles, with unsurpassed facilities for ready intercommunication by street railways, renders possible separate comfortable homes for the working population, and thus tends to elevate their condition and increase their efficiency. Such and so vast a class of skilled mechanics is therefore available from which to recruit the forces of the establishment when necessary. Under their command are special tools, which have been created from time to time with reference to every detail of locomotive-manufacture; and an organized system of production, perfected by long years of experience, governs the operation of all.
With such a record for the past, and such facilities at its command for the future, the Baldwin Locomotive Works submits the following Catalogue of the principal classes of locomotives embraced in its present practice.
CIRCULAR.
In the following pages we present and illustrate a system of STANDARD LOCOMOTIVES, in which, it is believed, will be found designs suited to all the requirements of ordinary service.
These patterns admit of modifications, to suit the preferences of railroad managers, and where machines of peculiar construction for special service are required, we are prepared to make and submit designs, or to build to specifications furnished.