Carbon steel rail fish plate Fishtail plate in the railway transport has a very important role,its main role is to play the role of connecting two sections of rail joint using Glued insulated fish plate,it is a piece of about 60 cm long steel plate,both ends have four or six hole steel bolt,used to buckle in the rail of small holes. There is a special gap between the rails,about 6mm wide,called expansion joint.The small holes through the steel bolts on the BS standard fish plate of the rail are oval in shape so that the rail has room to expand in hot weather,which is very important for the rail.