Lever Lever A lever ( or ) is a simple machine consisting of a beam or rigid rod pivoted at a fixed hinge, or fulcrum. A lever is a rigid body capable of rotating on a point on itself. On the basis of the location of fulcrum, load and effort, the lever is divided into three types. It is one of the six simple machines identified by Renaissance scientists. A lever amplifies an input force to provide a greater output force, which is said to provide leverage. The ratio of the output force to the input force is the mechanical advantage
Lever frame Lever frame Mechanical railway signalling installations rely on lever frames for their operation to interlock the signals, track locks and points to allow the safe operation of trains in the area the signals control. Usually located in the signal box, the levers are operated either by the signalman or the pointsman. The world's largest lever frame (191 levers) is thought to have been in the Spencer Street No.1 signal box in Melbourne, Australia, which was decommissioned in 2008. The largest operational lever frame, meanwhile, is located at Severn Bridge Junction in Shrewsbury, England, and it contains 180 levers, although most