Appeal from the District Court of the United States for the Eastern District of Pennsylvania; William H. Kirkpatrick, Judge.
Before BUFFINGTON, WOOLLEY, and THOMPSON, Circuit Judges.
Two appeals, Nos. 5137 and 5138, are here involved. In the court below the appellants, hereafter called plaintiffs, brought suit against the Bethlehem Steel Company, hereafter called defendant, on ten patents. On final hearing that court dismissed the bills, holding that forty-one claims of such patents were invalid and nineteen were not infringed. Whereupon these two appeals were taken on eight of the patents and are both disposed of in this opinion.
Some of these patents were in issue in the District Court for the Southern District of New York and in the Circuit Court of Appeals of the Second Circuit. See Ingersoll v. Delaware & Hudson Co., 37 F.2d 465. Reference to these two opinions for information saves needless repetition on our part.
Broadly speaking these patents aim to increase the efficiency of locomotives by equipping them with auxiliary engines which, in the speech of the art, are called "boosters." The use of boosters in some form is almost as old as locomotives themselves, the American patent of Cathcart, No. 6818, dating back to 1849, and their general use is shown by the British patent of Sturrock, No. 40,715, in 1863, the German patent No. 202,831 of Liechty in 1904, and the patent of Helmholtz, No. 516,436, in 1894, embodied in the Krauss engine of the Bavarian State Railways. In that regard the plaintiffs concede: "It is frankly recognized that the broad idea of applying an auxiliary motor to a locomotive for the driving of wheels to supplement the main driving wheels, was suggested long ago in this art -- in fact as far back as a half a century or more."
The problem of a locomotive itself increasing its efficiency by increasing its weight or increasing the number of its driving wheels is one method, or, on the other hand, by utilizing through an auxiliary booster engine the nontractive, supporting front or rear wheels on the locomotive or those supporting the tender. As illustrative of the situation, we quote the accurate and enlightening statement in plaintiffs' brief, as follows:
"The "booster" is a small, auxiliary propulsion unit for a locomotive and is used to supplement the main driving means of the locomotive in starting a train and drawing it at slow speeds and on grades. It is not used at high speeds, under which condition its drive is disconnected. It is intended to enable the locomotive to start and draw a heavier train than the locomotive could otherwise start and draw in the absence of such an auxiliary.
"Such a device can be employed because every locomotive has a boiler which is capable of generating enough steam for high-speed operation. This is more steam than is needed in starting and at low speeds. The boiler therefore has surplus steam available in starting and at low speeds. The booster uses this surplus steam, converting it into draw pull at the time it is most needed.
"Practically every locomotive has idle, weight carrying wheels in addition to its larger driving wheels -- this for the purpose of distributing the weight. These wheels and their axles are mounted in truck frames pivoted to the main frame of the locomotive and to the frame of the tender of the locomotive."
The defendant's brief thus describes it:
"A train of cars requires greater pulling force to start it from rest than is required for keeping it in motion in normal running after it is once started, because, in starting, the inertia of the weight of the train and static friction must be overcome. Also, greater force is required to pull a train up a grade than in running on the level.
"The pulling force is exerted by the driving wheels of the locomotive which are caused to revolve by the engine on the locomotive. Those wheels support a large part of the weight of the locomotive, so that, when the wheels are caused to revolve, there is considerable friction between the treads of the wheels and the rails, and thus the locomotive tends to move forward and exert a pull on the train. If, however, the train is very heavy, the tractive effect, due to the friction between the treads of the driving wheels and the rails, may not be sufficient to move the train, in which event the driving wheels, instead of rolling forward on the rails, will merely slip on the rails and be revolved without exerting any substantial tractive effect.
"So the pulling force available for starting a train is dependent not only on the power of the locomotive engine but also upon the tractive effect as between the driving wheels and the rails.
"The locomotive engine, at starting and in ascending grades, commonly has a large surplus of power available for causing the driving wheels to revolve. The limiting factor then becomes the tractive effect of the driving wheels on the track rails. If that tractive effect could, in some way, be increased, ...