Catenary is the general term used for the overhead wire used to feed electricity to trains, and is applied as a general term for all of the above-track wiring. The actual wire from which the electricity is collected is known as the “trolley” wire. The word “catenary” comes from the latin word catena, meaning “chain”, which is used to describe the mathematical curve of a flexible wire suspended between two fixed endpoints. Since the wire carrying current needs to remain in contact with the collection device attached to the train, a varying height is obviously a problem, particularly as speeds increase and spring-loaded contact devices cannot keep up with rapid height changes. Support structures evolved to hold the power-feed wire at a constant height, and the most common of these uses a second wire in the shape of a catenary curve with varying-length “dropper” wires attached to the trolley wire to hold it level (some more complex systems use more than one supporting wire).
Also carried on the overhead structure are supply lines carrying the voltage used on the catenary (using heavier wire to reduce loss) and high-voltage lines used to supply transformers along the line that power individual electrical sections. Some photos of Transformer buildings can be found on the Electrical Images page, and more information about catenary systems can be found on the Prototype Catenary page.
Kii-Arita Station DC Catenary, Kisei Line, Wakayama (2002)
Catenary at Sugimotocho Station, Ōsaka (2007)
Ome Line Catenary, Tōkyō (2009)
Tōkaidō Shinkansen Catenary (2008)
Curved-pole Catenary on the Chūō Line, Tōkyō (2009)
Older-style Catenary on a Shinkansen Line, Aomori (2006)
Photographers: 海爾渥 / Hairworm
Shinkansen Station Catenary, Himeji (2005)
Photographer: Aleksander Dugnes
Commuter Station Catenary (note the two different supports, one for the messenger wire and one for the catenary) (2007)
Shinkansen Station Catenary between roofs, Kyoto (2008)
Photographer: Arnoldo Riker