Fig. 26 indicates a weigh-shaft with the three levers, that are usually connected, by Avhich motion is transmitted from one to the other. The levers are distinct from the shaft, and are keyed to it, sometimes near each other, and at other times near the two extremities of the shaft; the whole arrangement depending upon the length of the shaft or spindle, and the width and class of engines for which the levers are designed.

That lever which is indicated by L B in the Figure, transmits all its moving power to the shaft and the other two levers; consequently, the lever L B is one class of prime mover of the weigh-shaft. When this lever is fixed midway between the other two levers, instead of being at one end of the shaft, the arrangement is suitable for some classes of land engines, and tends to an equal distribution of the friction, and consequent equal wear of the bearing surfaces.

Soft steel is suitable for weigh-shafts, by reason of the closeness of its texture, which facilitates the production of good friction surfaces, and because of the superior strength of steel as manifested in its resistance to torsion.