A four-quadrant gate is a type of boom barrier gate protecting a grade crossing. It has a gate mechanism on both sides of the tracks for both directions of automotive traffic. The exit gates blocking the road leading away from the tracks in this application are equipped with a delay, and begin their descent to their horizontal position several seconds after the entrance gates do, so as to avoid trapping highway vehicles on the crossing. Four-quadrant gates are safer than two-quadrant gates because they prevent drivers from illegally driving their vehicles around lowered gates to try to beat a train.
In the UK, such crossings are categorised as 'Manually Controlled Barriers' (MCB) because they are always manually controlled, usually from a signal box. Some are known as MCB-CCTV level crossings, because they are supervised by video link to the signal box from which they are remotely controlled.
Read more about Four-quadrant Gate: Automatic Full Barriers
Famous quotes containing the word gate:
“I have come to the conclusion that the major part of the work of a President is to increase the gate receipts of expositions and fairs and by tourists into town.”
—William Howard Taft (1857–1930)