Electrical Testing and Inspection Procedures

Ensuring wiring connections match the approved wiring diagram.

Testing each wire for continuity and insulation before connecting relays.

Checking the number of wires connected to each terminal to match wiring diagrams.

Testing relay contact allocation and wire counts before continuity and insulation tests.

System for adding or removing wires, usually with color coding (e.g., red for adds, green for deletes).

Checking each circuit's control through designated relay contacts according to the wiring diagram.

Checking each individual path(s) in parallel, if a device is fed through multiple paths.

Ensuring proper grounding of equipment like lightning arrestors and others in AC electrified areas.

Unwanted power or signals interfering with the system's operation.

Issues with a relay causing erratic or incorrect signals.

Comprehensive testing of both indoor and outdoor signaling equipment for safety and functionality.

Testing indoor wiring using a simulation panel featuring field equipment before outdoor connections.

Track circuits, Automatic train control, and axle counters used to track train presence.

Cables for signaling systems need testing per specifications.

Signalling power systems must follow guidelines listed in the relevant chapter.

Changes or modifications to interlocking systems.

Tests to confirm that a signal's cleared route can't be changed if the track circuit ahead is de-energized.

Route release controlled by multiple track circuits that ensures a complete route isn't released unless the entire track section ahead of it is clear.

Route release after a designated delay, triggered after a train occupies and clears the track circuit.

Tests to confirm that a route can't be changed until the signal indicator is active & a set delay passes.

Ensuring release of an overlap after last rear track circuit clears for berthing, testing the signal knob release, and related procedures for appropriate operation.

Procedures for verifying that signal indications match the physical aspects displayed on site and confirming the correct functionality of all signal aspects.

Ensuring the displayed signal aspect corresponds to its physical state (ON/OFF).

Verifying the functionality of route indicator(s), confirming the signal's indication relay isn't activated until sufficient lamps/LEDs are lit.

Verifies that a point can only be operated to its normal position after all track circuits controlling it are shunted.

Ensures that when an obstruction is present in the point, the overload relay cuts off power to the motor, preventing damage.

Confirms that point indication relay does not energize when the point lever is operated but the point machine is disconnected.

Verifies that the detection relay accurately reflects the point's position, and that indication in the cabin/panel matches the actual position.

Ensures that when the crank handle is removed, the signals for the corresponding route cannot be taken 'OFF' and points cannot be operated remotely.

Checks that the detection relay is de-energized when an obstruction is detected, and displays this in the cabin/panel.

Confirms the point indication relay remains de-energized even when the point lever is operated in case the point machine is disconnected.

Verifies the operation of the detection relay to the correct position by manually making and breaking the point detector contacts at site.

Ensures a point remains locked in its chosen position even after an attempt to change the route. This prevents accidental track changes.

Prevents unauthorized route changes while a train is approaching a signal. The signal remains 'ON' and the route stays locked until the train passes or a time delay expires.

Ensures only one signal route is active at a time. Clearing one signal route prevents clearing another signal, maintaining safety.

Detects the presence or absence of a train on a specific track section. The signal will go 'ON' when a train enters the section and remain 'ON' until the train exits.

Provides backup track circuits to ensure reliable train detection even if one circuit fails. This enhances system safety.

Maintains the signal route locked while the train occupies the following section of track. This prevents another train from entering the occupied section.

Controls the level crossing gate based on the signal state. The gate is closed when the signal is 'OFF' and opens when the signal is 'ON'.

The signal route is released when the train clears the track section and the time delay expires. This allows the signal to go 'OFF' and other routes to become available.

A feature that ensures interlocking systems only allow specific signal or route settings based on predetermined conditions, such as the position of other signals or track sections. This is crucial for preventing unsafe or conflicting train movements, especially in scenarios like alternate overlap or parallel track movements.

These circuits gather and store data from various components within a signaling system, such as power supplies, relays, block instruments, battery chargers, and alarm monitoring systems. This data is then used for maintaining, troubleshooting, and improving the overall performance of the system.

This refers to various important but often less-focused-on circuits crucial for the overall safety and functionality of a signaling system. These circuits include features like the effectiveness of station master's keys, cascading of signals, red lamp protection, lightning arrestors, surge protectors, and ensuring that relay contacts are paralleled where possible.

These are safety protocols that must be followed during testing and maintenance of signaling systems to prevent dangerous situations or damage to equipment. These precautions include: 1. Never change a signal from 'OFF' to 'ON' while a train is approaching. 2. Never set a signal that could cause a conflicting or unsafe movement. 3. Never disturb a point or isolation in a route set for a moving train. 4. Never energize a track relay when the track circuit is occupied by a train. 5. Never apply voltage beyond permissible levels to the equipment. 6. Always avoid the risk of electric shock to personnel.

These tests are performed to check the level of insulation in the signaling cables, essential to prevent leakage of current and ensure the proper function of circuits. These tests are crucial for safety and must be done according to detailed procedures outlined in the relevant chapter of the signaling manual.

Maintaining the cleanliness of LED lenses in signaling systems is crucial for proper signal visibility and recognition by train drivers. This requires using a dry, lint-free, and abrasive-free cloth to maintain the clarity of the lenses.