Beugniot lever

The Beugniot lever (Beugniot-Hebel) is a mechanical device used on a number of locomotives to improve curve running.

Around 1860, when Beugniot was the chief engineer at the firm of André Koechlin & Cie. in Mulhouse, he developed a system whereby wheelsets are housed in pairs in the locomotive frame, with side-play, and connected by a lever.

These levers are fixed to the frame in the centre and thus enable the sideways movement of the connected axles in opposite directions.

By enabling this transverse movement of the wheelsets, locomotives with rigid frames do not have to use the thinner wheel flanges etc.

normally needed to facilitate smooth running through points, bends and tightly curved sections of track.