The structure gauge, also called the minimum clearance outline, is the minimum height and width of tunnels and bridges as well as the minimum height and width of the doors that allow a rail siding access into a warehouse. In addition, the term may apply to the minimum distance to railway platforms (passenger or freight), buildings, electrical equipment boxes, railway signal equipment, third rails or to supports for overhead catenaries 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.
The term structure gauge can also be applied to the minimum size of road tunnels, road bridges etc.
Famous quotes containing the word structure:
“Why does philosophy use concepts and why does faith use symbols if both try to express the same ultimate? The answer, of course, is that the relation to the ultimate is not the same in each case. The philosophical relation is in principle a detached description of the basic structure in which the ultimate manifests itself. The relation of faith is in principle an involved expression of concern about the meaning of the ultimate for the faithful.”
—Paul Tillich (1886–1965)