Railway

A Railway Bridge . The bridge deck is not supported by any piers or supports but it is held by a movable support . A 3 wheels with belt used to be run under the deck and in the time the train comes to the bridge edge , the support moves under the train in the train direction . And there is a distance to be calculated between the supports under the train . It is gonna be a continuous beam or 1 middle span with two cantilever . And it is to be designed by the live load and the influence lines functions .