A device for locking a switch blade with a stock rail which includes a locking piece connected to the stock rail. The locking piece has an opening through which the longer leg of an L-shaped locking clamp extends. A switch element also extends through the opening and has an upper surface in contact with the longer leg of the L-shaped member which extends below the foot of the switch blade. The shorter leg has an end free to articulate with respect to a shaft. The shaft is further connected with a clamp receiver or clamp notch. The pivot axis of the clamp receiver member and shorter leg extends parallel with the switch blade and is positioned above the foot of the switch rail such that the clamp receiver member slopes downwardly between the shaft and connection point with the switch blade. This arrangement avoids tipping of the switch as the vertical force vector of the resultant vector passing through the contacting surface of the switching element and first leg intersects the switch blade rail foot on a supporting base immediately adjacent to the switch blade rail foot.
