In the latter part of the year 1831 the late John B. Jervis invented what he called "a new plan of frame, with a bearing-carriage for a locomotive engine," for the use of the Mohawk & Hudson Railroad. Jervis's engine is shown by Figure 9. In a letter published in the American Railroad Journal of July 27, 1833, he described the objects aimed at in the use of the truck as follows:
The leading objects I had in view, in the general arrangement of the plan of the engine, did not contemplate any improvement in the power over those heretofore constructed by Stephenson & Company,[11] but to make an engine that would be better adapted to railroads of less strength than are common in England; that would travel with more ease to itself and to the rail on curved roads; that would be less affected by inequalities of the rail, than is attained by the arrangement in the most approved engines.
Fig. 9.—John B. Jervis's Locomotive, 1831,
and Plan of its Running Gear.
In Jervis's locomotive the main driving-axle, A, shown in the plan of the wheels and running gear, was rigidly attached to the engine-frame, a b c d, and only one truck, or "bearing-carriage," e f g h, consisting of the two pairs of small wheels attached to a frame, was used. This was connected to the main engine-frame by a kingbolt, K, as in Allen's engine.
The position of its wheels on a curve, and the capacity of the truck, or "bearing-carriage," to adapt itself to the sinuosities of the track are shown in the plan. The effectiveness of the single truck for locomotives, in accomplishing what Mr. Jervis intended it for, was at once recognized, and its almost general adoption on American locomotives followed.
In 1834, Ross Winans, of Baltimore, patented the application of the principle which Mr. Allen had proposed and adopted for locomotives "to passenger and other cars." He afterward brought a number of actions at law against railroads for infringement of his patent, which was a subject of legal controversy for twenty years. Winans claimed that his invention originated as far back as 1831, and was completed and reduced to practice in 1834. The dispute was finally carried to the Supreme Court of the United States, and was decided against the plaintiff, after an expenditure of as much as $200,000 by both sides. It involved the principle on which nearly all cars in this country are now and were then built; and, as one of the counsel for the defendants has said, "It was at one time a question of millions, to be assured by a verdict of a jury."
In 1836, Henry R. Campbell, of Philadelphia, patented the use of two pairs of driving-wheels and a truck, as shown in Figure 10. The driving-wheels were coupled by rods, as may be seen below. This plan has since been so generally adopted in this country that it is now known as the "American type" of locomotive, and is the one almost universally used here for passenger, and to a considerable extent for freight, service. An example of a modern locomotive of this type is represented by Figure 11.
Fig. 10.—Campbell's Locomotive.