Pull-Off

Definition

A pull-off is an insulated assembly designed to pull the messenger and contact wire to a specific stagger from the center of the track, as specified by the design team. This assembly is connected to one pole.

Purpose

The purpose of a pull-off is to maintain the correct position and tension of overhead wires in railway or transit systems, ensuring safe and reliable electrical contact with trains or trams.

Examples of Use

• In electric rail systems, pull-offs are used to position and tension the catenary wires that supply power to trains.
• Tram systems employ pull-offs to maintain the alignment of overhead wires through curves and switches.
• Pull-offs are utilized in trolleybus networks to ensure the contact wires are properly aligned with the vehicle's pantograph.

Related Terms

• Catenary System: An overhead wire system used to supply electricity to trains, trams, or trolleybuses.
• Messenger Wire: A wire that supports the contact wire in an overhead catenary system.
• Pantograph: A device mounted on the roof of electric trains, trams, or buses to collect power from overhead wires.

Notes

Pull-offs must be precisely installed and maintained to ensure the stability and efficiency of the overhead electrical supply systems in transit networks.