What is track circuit failure?

What is a track circuit failure? A track circuit failure can delay trains because the signalling system is designed to fail to a safe state. Potential causes of failures include a broken rail, a blown fuse, faulty electrical parts, cable theft, or a loose connection, all of which form a break in the track circuit.

How does a track circuit work?

Track circuits work by running a circuit using the rails to connect a power source at one end of the block with a relay at the far end. The relay and power source are connected to each rail by cables. If the circuit is complete, the relay will be energized, which keeps signals in the “clear” position.

What is track bonding plan?

The majority of running rails are used to form track circuits to provide a means of proving the absence of trains. The General arrangement is that a low power signal is transmitted from ans end of the track circuits, along one rail, to a receiving device.

How long is a track circuit?

Every length of track in a signalled area is split up into logical sections called ‘track sections’ or ‘blocks’. For example, on the main line, each track section is about 100m long. In this case, a signal is placed at the start of each track section to indicate whether the section ahead is ‘occupied’ or ‘clear’.

What is railway track circuit?

A Track circuit is an Electrical circuit of which the running Rail of a Railway track forms a part. It is employed for indicating the presence of Trains and thereby for controlling Signalling and Block equipment.

What is DC track circuit?

Track circuit is designed to know whether the portion of rail (track circuited) is clear or occupied by a train. A D.C. track circuit has two ends i.e. feed end and relay end. Both the ends are insulated by a Nylon joint or glued joint. It is short-circuited by any means.

What is Transverse bond?

2.2 “Cross-bond” means a bond between two rails of a track or two rails of adjacent tracks. It is also called a ‘transverse bond”. 2.7 “Rail-bond” means an electrical connection across a rail joint between consecutive lengths of rails. It is also called a “Longitudinal bond’.

What is Relay in railway?

Relay is an electromagnetic device which is used to convey message electrically from one circuit to another circuit through a set of contacts (back or front contacts)and works on the principle of electromagnetism. Relays are classified as : According to source of power applied – DC Relays & AC Relays.