Track Circuit Length and Configuration Quiz

<p>Install insulating sleeves and ensure clearance (D)</p> Signup and view all the answers

<p>100 meters (D)</p> Signup and view all the answers

<p>Cross bonding (B)</p> Signup and view all the answers

<p>Double rail only (C)</p> Signup and view all the answers

<p>Crossing the track circuit rail with uninsulated rail (C)</p> Signup and view all the answers

<p>The return rail shall be staggered (A)</p> Signup and view all the answers

<p>Approved type of AC immunised track relays (C)</p> Signup and view all the answers

<p>AFTC should only be maintained and not newly installed (D)</p> Signup and view all the answers

<p>750 meters (B)</p> Signup and view all the answers

<p>300 Amperes (D)</p> Signup and view all the answers

<p>Restrictions can be relaxed up to 450 meters (C)</p> Signup and view all the answers

<p>8.8 V (B)</p> Signup and view all the answers

<p>Retain existing length at higher catenary current (D)</p> Signup and view all the answers

<p>10 milli-amperes (B)</p> Signup and view all the answers

<p>Another type of track circuit suitable for A.C. traction area (A)</p> Signup and view all the answers

<p>At the IRJs (Insulated Rail Joints) (D)</p> Signup and view all the answers

<p>100 milli-amperes (B)</p> Signup and view all the answers

<p>O.H.E masts or other structures (A)</p> Signup and view all the answers

<p>Both rails must be balanced with respect to earth and current flow (D)</p> Signup and view all the answers

<p>Approved type impedance bonds (B)</p> Signup and view all the answers

<p>Examination for harmonics generated (C)</p> Signup and view all the answers

<p>25 V (D)</p> Signup and view all the answers

<p>To improve the speed of trains (C)</p> Signup and view all the answers

<p>Track layout and electrification structures (C)</p> Signup and view all the answers

<p>The track circuit rail (B)</p> Signup and view all the answers

<p>Avoid bonding disconnection (C)</p> Signup and view all the answers

<p>Signal department (C)</p> Signup and view all the answers

<p>Due to traction return considerations (B)</p> Signup and view all the answers

<p>430 V (D)</p> Signup and view all the answers

<p>They must handle a peak load of 1000 Amperes for up to five minutes. (D)</p> Signup and view all the answers

<p>DC traction current ratings are typically higher than those for AC impedance bonds. (B)</p> Signup and view all the answers

<p>PVC (B)</p> Signup and view all the answers

<p>The signaling and telecommunications (S&amp;T) department (A)</p> Signup and view all the answers

<p>Cross bonds and sub-station current return busbars (C)</p> Signup and view all the answers

<p>They should not impede mechanised track maintenance or pose hazards to personnel. (D)</p> Signup and view all the answers

<p>Its integrity is crucial for the operation of track circuits. (D)</p> Signup and view all the answers

<p>400 Amperes continuously (A)</p> Signup and view all the answers

<p>100 meters (D)</p> Signup and view all the answers

<p>Cross bonding must be provided at both ends (A)</p> Signup and view all the answers

<p>To carry full traction return current (C)</p> Signup and view all the answers

<p>Impedance bond (A)</p> Signup and view all the answers

<p>8 SWG galvanized steel wires (C)</p> Signup and view all the answers

<p>Signaling and Telecommunication department (D)</p> Signup and view all the answers

<p>To enhance electrical continuity (A)</p> Signup and view all the answers

<p>Must be extended 50 meters (A)</p> Signup and view all the answers

The maximum length of a track circuit is determined by factors like ballast resistance, frequency, track layout, and the vendor (AFTC). It's generally limited to 700 meters in end-fed mode.

Automatic Train Control Function (AFTC) is not for new track construction. Existing AFTC systems should be maintained.

In this track circuit configuration, one rail is reserved for traction return current (uninsulated rail). All overhead line connections and return current connections go to this uninsulated rail.

The rail in a single-rail DC track circuit that carries the return current for traction.

Connections from overhead equipment (OHE masts) are made to the uninsulated rail in single-rail DC track circuits.

Connecting adjacent uninsulated rails to prevent heavy current flow from a break in the uninsulated rail, typically done at intervals not exceeding 100 meters.

Track circuits on AC electrified sections can use IRJs (Insulated Rail Joints) or ESJs (electrical separation joints) and can be configured as single or double rail track circuits. Track circuits using ESJs must be double rail.

Maintenance schedule for AFTC systems is found in Annexure: 17-MS3.

The maximum distance a DC track circuit can span, limited by the return current and type of relay used.

In adjacent track circuits, the return rails should be offset to prevent interference.

Track relays must be designed to withstand interference from AC traction voltages.

Length of DC track circuits is limited by rail return current. Increased AC immunity allows longer circuits.

A specific type of track relay that can handle longer DC track circuits.

Length restrictions caused by concrete sleepers can be reduced if the ballast resistance meets certain standards.

A type of track relay with improved AC immunity, allowing for longer track circuits.

An additional 'B' type choke is installed in series with the track relay on double track sections to protect the system.

For single-track sections, catenary current exceeding 300 Amperes requires an AFTC; for double-track, it's 600 Amperes.

Before installing single-rail DC track circuits in AC areas, measure stray DC currents to ensure they are within limits.

If the track circuit is less than 100 meters, the total stray current must be 10 milliamperes or lower.

If the track circuit is 100 meters or more, the total stray current limit is 100 milliamperes.

In double-rail AFTC circuits, impedance bonds are used at IRJs to balance current flow in each rail.

Audio Frequency Track Circuits in RE areas must be configured as double rail circuits, ensuring both rails are balanced with respect to earth and current.

Impedance bonds are required in audio frequency track circuits, especially where a specific design does not address balancing the traction rail return current, or when used with 50Hz electrified lines.

DC impedance bonds have higher current ratings than AC impedance bonds.

AC impedance bonds can support 400 Amps continuously (200 Amps per rail), and 1000 Amps peak for up to 5 minutes without damage.

Lead cables between impedance bonds on the same track must be PVC sheathed cables with compression lugs.

Impedance bond installation must ensure safety for maintenance personnel and not pose a hazard for those walking around the tracks.

The S&T department handles connections between rails and impedance bonds, along with bonds on the same track.

The electrical department is responsible for cross-bonds, earth wires, connections to substation current return busbars, and connections to booster transformers (terminated on the centre tap of impedance bonds).

The operation of a track circuit relies on the integrity of the traction return bonding, which is essential to test during installation and maintenance.

Follow RDSO's guidelines when installing and maintaining track circuits in the railway area.

To prevent excessive current flow due to a break in the uninsulated rail, adjacent tracks are connected at intervals no greater than 100 meters.

A continuous earth wire on the traction mast carries the traction return current. The uninsulated rail is connected to each mast by a structure bond.

No structure bonds, cross bonds, or connections to earth wires are allowed in double rail track circuits.

If necessary, a special impedance bond creates a neutral point for connections in double rail track circuits.

Rail joints in track circuited areas are bonded using two 8 SWG wires, secured by channel pins or welding/riveting.

Rail bonds are installed and maintained by the electrical department. Cross bonds are also their responsibility.

On a non-track circuited track adjacent to a track circuit, longitudinal bonding is extended 50 meters beyond the circuit.

The two rails of a non-track circuited track are bonded together immediately after the block joints.

Track bonding ensures a safe and reliable traction return path, prevents overvoltage, keeps track circuits operational, and minimizes damage from short circuits during normal and abnormal conditions.

A collaborative process involving electrical, signal, and structural departments to plan and implement track bonding through detailed drawings and specifications.

The track circuit rail is bonded in series to prevent wrong side failures from defective bonding and to ensure interruption of the conductive path in case of disconnection.

Traction return rails cannot be bonded in series due to the traction return considerations, to avoid loss of train shunt. Using alternate bonding methods is essential.

The rail used to detect the presence of trains within a specific track area..

Points where the rails are separated electrically to create sections for track circuits. The purpose is to isolate sections of a circuit if a break in the track circuit occurs.

The interruption or the severance of a conductive path between the track circuit connections and the relay or receiver end, ensuring that a fault in one area is isolated. It's critical.

Bonding is the electrical connection between the rails and components of track circuits in an area.