Mechanical Description of the Pioneer
Figure 11.—“Pioneer,” about 1901, scene unknown. (Photo courtesy of Thomas Norrell.)
After the early 1840’s the single-axle locomotive, having one pair of driving wheels, was largely superseded by the 8-wheel engine. The desire to operate longer trains and the need for engines of greater traction to overcome the steep grades of American roads called for coupled driving wheels and machines of greater weight than the 4—2—0. After the introduction of the 4—4—0, the single-axle engine received little attention in this country except for light service or such special tasks as inspection or dummy engines.
Figure 12.—The “Pioneer” in Carlisle, Pa., 1901. (Photo courtesy of Thomas Norrell.)
There was, however, a renewed interest in “singles” in the early 1850’s because of W. B. Adams’ experiments with light passenger locomotives in England. In 1850 Adams built a light single-axle tank locomotive for the Eastern Counties Railway which proved very economical for light passenger traffic. It was such a success that considerable interest in light locomotives was generated in this country as well as in England. Nearly 100 single-axle locomotives were built in the United States between about 1845-1870. These engines were built by nearly every well-known maker, from Hinkley in Boston to the Vulcan Foundry in San Francisco. Danforth Cooke & Co. of Paterson built a standard pattern 4—2—4 used by many roads. One of these, the C. P. Huntington, survives to the present time.
The following paragraphs describe the mechanical details of the Pioneer as it appears on exhibition in the Smithsonian Institution’s new Museum of History and Technology.