Fixed Signals
On most railways, physical signals are erected at the lineside to indicate to drivers whether the line ahead is occupied and to ensure that sufficient space exists between trains to allow them to stop.
Read more about this topic: Railway Signalling
Famous quotes containing the words fixed and/or signals:
“Montesquieu well knew, and justly admired, the happy constitution of this country [Great Britain], where fixed and known laws equally restrain monarchy from tyranny and liberty from licentiousness.”
—Philip Dormer Stanhope, 4th Earl Chesterfield (1694–1773)
“The term preschooler signals another change in our expectations of children. While toddler refers to physical development, preschooler refers to a social and intellectual activity: going to school. That shift in emphasis is tremendously important, for it is at this age that we think of children as social creatures who can begin to solve problems.”
—Lawrence Kutner (20th century)