Structure gauge

From Wikipedia, the free encyclopedia

The structure gauge, also called the minimum clearance outline, is the minimum size of tunnels and bridges as well as the minimum size of the doors that allow a rail siding access into a warehouse. In addition the term may also apply to the minimum distance to passenger railway platforms or freight railway platforms as well as the minimum distance to buildings, electrical equipment boxes, railway signal equipment, third rails and to the supports for overhead catenary or overhead lines from the track. The difference between the structure gauge and the loading gauge is called the "clearance".

The amount of clearance between the loading gauge and the structure gauge depends on the speed of the train, due to the train wobbling, so a train may be able to get past a restricted clearance by travelling at slow speed.