i) Neutral section: Passing of pantograph under insulated overlap will cause short circuit between two phases of the supply system, damaging OHE & pantograph. To avoid this bridging of two different sections fed by two different phases, a neutral section is inserted between them. Located between two substations.
ii) Section insulator: Section insulators are provided to insulate OHE of one elementary section from the OHE of another adjacent elementary section. Located at cross over from one track to other, from main line to siding.
iii) Un-insulated overlap: Two contact wires belonging to two adjacent sub elementary sections running parallel to each other for one span are electrically connected by jumpers. This is called as uninsulated overlap. To rectify faults in one contact wire of two running in parallel wires without affecting power to OHE. Located at two adjacent sub-elementary sections.
iv) Insulated overlap: To provide isolation for operation and maintenance of OHE if two lengths of OHE belong to two elementary sections. Located at feeding posts, sub sectioning posts and booster sections.