PTA OLE operates at a nominal 25,000 Volts, 50 Hertz, alternating Current (25kV,
50Hz, AC).
The OLE consists of concrete or steel masts, to which are attached Live cantilever
frames supported on insulators. The Catenary Wire is attached to the top of the
cantilever frames and the Contact Wire is suspended from the Catenary Wire by
means of droppers. Also mounted on the masts are a Live Return Conductor and an
Earth Wire. A Return Conductor must be treated as Live and dangerous at all times.
Overhead Conductor Rail is installed on the PTA Network in specific tunnels with
reduced electrical clearance.
The traction return system includes all conducting components which form a
conducting path for the traction return Current in normal operation and in the case of
fault scenarios.
The return circuit includes:
running rails;
return Current rails;
return Current Conductors or Return Conductor (RC);
Earth Wires;
bonding;
return Current cables; and
all other components conducting return Currents.