Circuit Design and Control Panels

Installation control principle where routes are controlled by entrance and exit push buttons.

Installation where routes are set individually, and signals are cleared via individual buttons or switches.

Setting point positions individually.

Method for point operation during track circuit failure.

Control of connections for adjacent equipment (cabins, crossings, etc.).

Interrupting connections via a group cancellation button.

Use of various colors for switches/buttons to differentiate functions such as running, shunting, etc.

The ability to select and set different routes and overlaps, important for handling alternate accesses to a location.

A red light indicates a stop signal is 'ON', and a yellow light indicates a permissive signal is 'ON' on the control panel.

A green, yellow, or double yellow light on the control panel indicates a stop/permissive signal is 'OFF'.

If the 'OFF' signal aspect doesn't light up, the corresponding symbol on the control panel will flash to indicate a failure.

On a domino panel with limited indication, a green light with flashing red/green combinations indicates various signal failures.

A white light strip or two miniature white lights on the control panel indicate a shunt signal is 'ON'.

A slanting white light strip or two miniature slanting white lights indicate a shunt signal is 'OFF'.

A white light below the signal symbol on the control panel indicates the signal is set for automatic working.

A white light below the running signal indication indicates a 'Calling-on' signal is 'OFF'.

The signal for a route will only clear if the SM's key is in, the interlocking is free, the points are set, locked, and detected, and other conditions (like track circuits) are met.

Full release of a route happens once the signal returns to 'ON' and the route switch/button is operated. Sectional release only releases specific parts of the route, allowing setup of other routes when there are many route sections.

Routes controlled by a single track circuit release after a predetermined time delay, but only if the track is empty.

A route section doesn't release just by picking up a track relay. It needs the next track circuit to drop and pick up, ensuring a train has passed through.

The last track circuit in a route can release even without another track circuit after it, because it's a berthing track.

Sectional route release is used in systems with many routes (over 100), allowing the setup of other routes while some sections are still being released.

In non-route setting systems, route release is similar to full release, but automatic release can be provided with sequence proving relays for train passage.

These relays verify an authorized train passage by monitoring a specific sequence of events. They are used in automatic route release in non-route setting systems.

A track circuit uses electrical current to detect the presence of a train on a section of track.

Axle Counters are used to detect trains by counting the axles that pass through a specific track section. They are designed for higher speed lines and can handle multiple trains.

Cables used in railway signalling systems to transmit control signals, power, and communication data.

Devices used to detect electrical leaks to earth in signalling cables, which can be a safety hazard.

The primary signals that control the movement of trains, typically multi-colour light displays.

Mechanical devices that control the position of railway points, allowing trains to be directed onto different tracks.

Point machines have multiple safety features like track circuit control, overload protection, and cross protection to prevent accidents.

Displays that show the route a train is to take, often with direction arrows or lighting patterns.

A key used to restore all signals to 'ON' aspect in an emergency when both control terminals and control panel fail. It is a crucial safety measure to ensure train operations can resume even in critical situations.

A self-restoring button that, when pressed along with the 'Extreme Emergency Key', restores all signals to 'ON' aspect. This button provides a secondary action to the key, enhancing redundancy and ease of use in emergencies.

A concept that ensures sensitive circuits are protected from accidental interference. This involves measures like double-cutting, preventing any malfunction or unintended interaction from affecting critical operations, maintaining system integrity.

Measures preventing external circuits from causing problems for crucial internal systems. These measures shield the system from induced voltages and cross-connections that could lead to instability or malfunctions.

A device that displays the layout of the yard and its current status clearly. It acts as the central interface for monitoring and controlling the signals, point positions, and overall train operations, ensuring a visual understanding of the system.

Having multiple control terminals that act as backups, ensuring fault-tolerance and smooth operation even if one fails. This redundancy is crucial to maintain system stability and provide continuous functionality in the event of a failure.

The specific way that controls and statuses are visually presented on the Control Terminal. This encompasses the symbols, colors, and arrangement of information to clearly communicate the state of points, signals, and other components of the system.

A legacy device used in older Electronic Interlocking (EI) systems, primarily replaced by Control Terminals. The Control Panel is an older interface for controlling and monitoring train operations within a smaller, more compact physical space.

The last position of a point (switch) is stored in the system, even after power is lost. This ensures the point can be restored to its last set position, providing safety and operational efficiency.

A safety feature that prevents a point from being moved while it's already being operated. It prevents accidental switching or interference during point movement.

A dedicated connection point in an electronic interlocking system designed for signal technicians to access and maintain the system. It assists in troubleshooting and repair.

A feature built into the Electronic Interlocking (EI) system that manages train movements within a block section. It ensures line clearance and safety by controlling signals and track sections.

A safety approach in system design where faults or failures result in the most restrictive action (e.g., stopping a train). This prevents accidents caused by equipment malfunctions.

A fail-safe technique where circuits are kept energized all the time. Any interruption or power loss triggers a safety response (e.g., displaying a stop signal).

The ability of a system to automatically detect failures in its components (e.g., relays, sensors). The system then takes appropriate action to ensure safety (e.g., setting signals to restrictive aspects).

Physical barriers or covers used to prevent external objects from causing short circuits in vital circuits. These shields protect the system from environmental hazards.