Railway Overhead Line Equipment
Overhead Line Equipment (OLE) includes
- Wires suspended over the railway line for supplying electricity to electric trains, including associated:
- Return conductors
Catenary wire and Contact wire
1. Catenary wire is carried on insulators or insulated supports attached to the structures.
2. Contact wire is suspended from the catenary wire by means of droppers.
3. Normal height of contact wire above rail level is 4.7 m(15 ft 5 inches) or 4.9 m (16 feet) according to design of OLE Normal minimum height at public road level crossings (for road vehicles of (16 ft 6 inches max. height ) is 5.6 m (18 ft 6 inches).
4. Contact wire is staggered (i.e. offset from track centre line) at structures.
On straight track – on alternate sides of centre line of track, so as to prevent grooving of contact surface of the pantograph On curved track generally to the outside of the curve to maintain contact wire within geometrical tolerances of its position on pantograph head.
Catenary – India and UK
India – Catenary is made of stranded Cadmium Copper Cable of about 65 sq.mm. section while Contact wire is grooved hard drawn Copper wire of 107 Sq.mm. cross‑section. (As per revised design, 150 sq.mm. wire is being used to cater for higher catenary current).
UK – Catenary shall be Alumoweld Alumunium conductor of following composition: 2/3.95 mm Alumoweld + 5/3.95 mm Aluminium Contact wire shall be in accordance with BS23 of 107 sq mm size of hard drawn copper in automatically tensioned territory and of hard drawn cadmium copper when used in fixed termination equipment.
- Neutral section
A short section of the OLE between two insulators introduced into the OLE and designated to make sure that two sections that must not be connected electrically are kept separated, even during the passage of the pantographs of electric trains.
- Terminal end
The point where OLE is finally terminated both in physical and electrical sense. In other words, it does not butt up to, or overlap with any other OLE.
A length of OLE between switching stations or a switching station and a terminal end.
- Sub – section
Part of a section that can be isolated from all other lengths of OLE by operating overhead line switches.
- A form of construction where the OLE is supported by wires suspended from masts on each side of track.
- A wire suspended across tracks and from which overhead line equipment is suspended.
Neutral Section in close up