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Unlike overhead line equipment, third-rail systems are not susceptible to strong winds or freezing rain, which can bring down overhead wires and hence disable all trains. Thunderstorms can also disable the power with lightning strikes on systems with overhead wires , disabling trains if there is a power surge or a break in the wires.
Pole Vault was the first operational tropospheric scatter communications system. It linked radar sites and military airfields in Greenland and eastern Canada by telephone to send aircraft tracking and warning information across North America.
In a movable bridge that uses a rigid overhead rail, there is a need to transition from the catenary wire system into an overhead conductor rail at the bridge portal (the last traction current pylon before the movable bridge). For example, the power supply can be done through a catenary wire system near a swing bridge. The catenary wire ...
A pole route (or pole line in the US) is a telephone link or electrical power line between two or more locations by way of multiple uninsulated wires suspended between wooden utility poles. This method of link is common especially in rural areas where burying the cables would be expensive.
Technicians require access to connection points. Placing such a point underground (e.g., in a utility vault) is expensive, so pedestals are preferred when they are an acceptable choice. Pedestals are used for CATV (known as a cable box in such a situation), telephone, passive optical networks, and other telecommunications systems.
The Division II pole vault national champion knew from others’ horror stories that a dwindling number of airlines were still willing to carry poles and that they were too long and cumbersome to ...
A vault is often accessible directly from a street, sidewalk or other outdoor space, thereby distinct from a basement of a building. [1] [2] Utility vaults are commonly constructed out of reinforced concrete boxes, poured concrete or brick. Small ones are usually entered through a manhole or grate on the topside and closed up by a manhole cover.
The conductor put the trolley pole onto the wire, and as the tram moved forward the conduit channel veered sideways to outside the running track, automatically ejecting the plough - the tram was said to be 'shooting the plough'. At the changeover from overhead wire to conduit the process was a little more complicated.