An expansion joint for part of a railway track arranged on a foundation has a stock rail with a stock rail head and a tongue movable with respect to and along said stock rail head, upon which at least one fastening device acts for pressing it on the stock rail. This expansion joint enables the rail foot to be longitudinally moved with little friction and excludes tipping of the stock rail or tongue. For that purpose, the tongue is not bolted but pressed only against the stock rail by the fastening device, and the force thus transmitted is decomposed into components that act on the one hand in the direction of the foundation and on the other hand in the direction of the stock rail head.