Track Circuit

A track circuit is an electrical circuit that uses the rails as a conductor. It con-
sists of an electrical source and a regulating resistance at one end and a low resistance safety relay at the other end.

The rails will be used as electric conductors. The power supply is connected
to the rail head of the rail. The relay is connected at the other end of the rail.
In most cases, the rail is insulated to help to improve the rail to ballast resistance. When there are no trains running, the relay receives electricity
from the power supply (track feed) is energize. When there are trains running, the relay will not receive electricity from the power supply and will be de-energized. Operation of the relay indicates whether a train is present within
the track circuit’s block section and a signal is fed back to the signalling interlocking system.

This track circuit equipment is composed with Track Feed Unit at feeding side of track section, Track Relay at receiving side of location cupboard and insulated rail joint, rail bonds, varicose connection wires. The track circuits can be used in electrified areas operating an AC immune track relay.

Type of products

Track Feed Unit(TFU)

The DC track circuit relay will be connected to rails and will receive the pick-up voltage via the rails from the feeding transformer and the rectifier as shown above. For protecting from the inductive voltage or current by the return traction current, for an electrified railway, the choke and damping resistor are included in the circuit. The damping resistor will limit the feeding current when
a train occupies the track section. The protective choke will limit the return traction current, generated because of the voltage difference between the rails.

The operating characteristics are as follows:-
• This track feed unit complies with former BRB Specification 867
• Supply voltage 110V ac 50Hz with tappings covering
the range 95V, 100V, 105V, and 110V
• Each track circuit shall be individually fed by a separate feed unit.
• Output via a fixed internal resistor, with output adjustment
provided by a ‘high’ and ‘low’ tap on the internal transformer to allow for variations in ballast conditions and track length.

Insulated Rail Joints: IRJ's

The Xenix insulated Steel Fishplate consists of a high strength steel bar to which is bonded the insulation layer and a steel face plate. The factory bonding ensures that maximum shear strength is obtained in between steel fishplate and faceplate. Supplied as a kit, the Xenix rail joint is installed in track using EPOXYLITE, a fast curing adhesive system which provides maximum tensile strength and fatigue life of the joint for the track.

For applications in which a field assembled, glued insulated rail joint is required. The Xenix joint kit is a proven solution. Using insulated steel fishplates produced in our plant, the insulating characteristics of the rail joint are guaranteed. The Xenix glued insulated rail joint is factory assembled to give guaranteed performance and extended life under the heaviest traffic conditions. Manufactured in our factory, the quality of Xenix insulated rail joint is ensured because of the close control all manufacturing and assembly operations.