Abstract: A railway wheel detector which is mechanically actuated by the flange of a railway wheel which engages a contacting surface of the detector which may be provided by a rigid plate. This surface is supported by blocks of compressible, resilient material, preferably a closed cell foam elastomeric material, which has more stiffness in a vertical direction than in a longitudinal direction (the direction along the railway track) so as to transmit forces for actuating the plunger of an electrical switch mechanism when the flange of the railway wheel contacts the contacting surface, but allows the contacting surface to move with the wheel to avoid wear, thereby providing reliable operation over a long life time. The switch is preferably hermetically sealed and the blocks of compressible, resilient material are preferably covered by a boot having bellows walls so as to enable the wheel detector to be installed outdoors on the rail of a railway track and to withstand severe environmental conditions.