Locomotive, marine, and all other engines which must be started in any position have at least two cylinders, and as many cranks set at an angle to one another. Fig. 19 demonstrates that when one crank, C 1 , of a double-cylinder engine is at a "dead point," the other, C 2 , has reached a position at which the piston exerts the maximum of turning power. In Fig. 20 each crank is at 45° with the horizontal, and both pistons are able to do work. The power of one piston is constantly increasing while that of the other is decreasing. If single -action cylinders are used, at least