A rail fastener device for directly affixing rapid transit system rail apparatus to a rigid support structure. The device includes a rail plate and a baseplate which are separated by a layer of elastomeric material which is bonded to the adjacent sides of each plate. Means are provided for fastening the rail directly to the rail plate, and means are provided for fastening the baseplate directly to the support structure. The rail plate, however, is free to float on the elastomeric material with respect to said baseplate so as to provide vibrational damping as well as electrical isolation therebetween.