|
Boom Barrier
A boom barrier, also known as a boom gate, is a bar, or pole pivoted to allow the boom to block vehicular or pedestrian access through a controlled point. Typically the tip of a boom gate rises in a vertical arc to a near vertical position. Boom gates are often counterweighted, so the pole is easily tipped. Boom gates are often paired either end to end, or offset appropriately to block traffic in both directions. Some boom gates also have a second arm which hangs 300 to 400 mm below the upper arm when lowered, to increase approach visibility, and which hangs on links so it lies flat with the main boom as the barrier is raised. Some barriers also feature a pivot roughly half way, where as the barrier is raised, the outermost half remains horizontal, with the barrier resembling an upside-down ''L'' when raised. Automatic boom barrier There are various technologies for an automatic boom barrier. One of them is electro-mechanical, which is widely used due to its reliability. The ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Crossbuck
A crossbuck is a traffic sign used to indicate a level railway crossing. It is composed of two slats of wood or metal of equal length, fastened together on a pole in a saltire formation (resembling the letter X). Crossbucks are sometimes supplemented by electrical warnings of flashing lights, a bell, or a boom barrier that descends to block the road and prevent traffic from crossing the tracks. Vienna Convention The Vienna Convention on Road Signs and Signals, a multilateral treaty of the United Nations with the intention of standardizing traffic signs around the world, prescribes several different regulations for the "crossbuck" sign. The sign should consist of two arms not less than long, crossed in the form of an . The first model may have a white or yellow ground with a thick red or black border. The second model may have a white or yellow ground with a thin black border and an inscription, such as "RAILWAY CROSSING". If lateral clearance obstructs the placement of the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
