U

Unclassified
Coach where the seating is not specifically classified for a particular class of passenger. Often applied to restaurant cars open to either class of passenger. q.v. Non-descript.

Underframe
The component of a carriage or wagon comprising the main structural part which carries the carriage body. Originally of wood, later strengthened by steel plates, and finally of all-steel construction, the underframe remained essentially a separate component until the introduction of the integral BR Mk.2 carriage design.

Unfitted Train
A train consisting of vehicles which are not fitted with continuous brakes. Special care is needed in working such trains as the only brakes available are those of the locomotive and brake van (controlled independently by the guard).

Up line
That line of a multi-track main line where the direction of travel is towards the major city (see also down line).

Upper-quadrant signal
A semaphore signal in which the signal arm is raised from the horizontal to give a clear indication.

Urie, R.W
Chief Mechanical Engineer for London, South Western Railway (1912-1922).