GER Category 3 key terms

The controlled document that sets out mandatory operating rules, definitions and instructions governing train movement, shunting, signalling and staff duties on the railway. Compliance is a condition of safety-critical certification.

Any task where a lapse in attention, judgement or health could directly endanger trains, passengers or trackside workers. It imposes stricter fitness, fatigue and conduct obligations than non-safety-critical work.

A signalling principle in which only one train may occupy a block section at a time, with the signal box ahead giving explicit acceptance before a train is allowed to enter. It prevents following collisions on lines without continuous colour-light control.

The length of line between two stop signals or signal boxes that a train must occupy exclusively under normal working. Its boundaries define where authority to proceed ends and the next must be obtained.

The explicit acceptance from the signal box in advance that the block section is free and a train may be admitted. It is the verbal or bell authority that underpins absolute block working.

A stop signal protecting the entrance to a station, junction or block section, which cannot be passed at danger without authority. It marks the limit of a driver's permitted movement until cleared.

A caution signal placed in rear of a stop signal to give advance warning of its aspect. It allows the driver to begin braking in good time and is identified by its distinctive shape or marking.

The visual indication displayed by a signal, such as green, yellow, double yellow or red, telling the driver what movement is permitted and at what speed. Aspects are read together with any associated route indicator.

An incident in which a train passes a stop signal without authority while it is displaying danger. It is reportable, investigated formally and may indicate driver error, signal sighting problems or adhesion issues.

A cab warning system that sounds a horn and displays a visual reminder when a train approaches a signal, requiring the driver to acknowledge it. Failure to acknowledge triggers an automatic brake application.

A trackside and onboard system that automatically applies the brakes if a train passes a signal at danger or exceeds a set speed at certain locations. It provides a safety overlay to the driver's own actions.

A supplementary display, such as a junction or platform indicator, that shows which diverging route a signal applies to. It must be read with the main aspect before the driver accepts the movement.

A physical or electronic object that gives a driver sole authority to occupy a single-line section. Only one token exists for a section at a time, preventing two trains from entering head-on.

A driver's detailed, examined familiarity with a route, including signals, gradients, speed restrictions, stations, junctions and landmarks. It must be maintained and refreshed to hold route competence.

The structured process of acquiring route knowledge, typically by travelling the route with a qualified driver, studying diagrams and being assessed. It ends in a formal sign-off for that route.

A document or diagram summarising the key features of a route, such as signals, speeds, gradients and stopping points. It supports route knowledge but does not replace practical learning.

The description of a line's rising and falling slopes, usually expressed as a ratio such as 1 in 100. It governs braking distances, starting capability and where trains may need assistance.

A temporary or permanent limit on train speed over a section of line, imposed for engineering work, track condition or infrastructure constraints. It is published in notices and must be observed precisely.

The planned relationship between speed, distance and brake force that allows a train to stop before a signal or restriction. It accounts for train weight, gradient, adhesion and brake performance.

The act of initiating braking, whether by service brake for controlled deceleration or emergency brake for maximum retardation. The method and rate depend on train type and conditions.

The maximum braking command available, applied when a collision, derailment or other immediate danger is perceived. It typically vents the brake pipe fully and cannot be released until the train has stopped.

The continuous pipe running the length of the train that transmits brake control signals and, when pressure is lost, causes brakes to apply automatically. Its integrity is essential to safe stopping.

The grip between wheel and rail that allows traction and braking forces to be transmitted without slipping. Low adhesion from leaves, ice or grease greatly extends stopping distances.

Loss of adhesion during acceleration or braking, causing wheels to spin or slide instead of rolling. It reduces control and can damage wheels, so drivers adjust power and brake technique accordingly.

A traction-enhancing treatment applied to rails in low-adhesion areas, especially during autumn leaf fall. It improves grip and is scheduled at known problem locations.

A formal instruction that a vehicle or unit must not be moved until a specific condition is met or authority is given. It protects defective, damaged or isolated vehicles from unintended movement.

Any unplanned event affecting the safe or normal running of trains, such as a SPAD, signal failure, derailment or near miss. Incidents are reported, logged and investigated to prevent recurrence.

A pre-defined sequence of actions to protect life and infrastructure in an emergency, such as stopping trains, isolating power and evacuating passengers. It is practised in training and drills.

The measures taken to prevent other trains from entering a section where an incident, obstruction or failed train exists. It may involve flags, detonators, signal protection or direct communication with signallers.

A small explosive device placed on the rail that detonates loudly when a train passes over it, alerting the driver to stop or proceed with caution. It is a key tool for protecting the line.

An unintended parting of a train, leaving vehicles running uncontrolled or stranded. It triggers emergency braking and requires immediate protection of the line and reporting.

A formally granted period during which a section of line is closed to normal traffic so engineering work can proceed safely. Trains may only enter under specific authority and conditions.

A method of running trains in both directions over one line while the other is blocked, using tokens, pilots or special instructions. It demands heightened vigilance and strict adherence to authority.

A competent person appointed to accompany a driver and give authority and guidance when normal signalling is suspended, such as during single line working. The driver follows the pilotman's instructions.

A published instruction informing staff of changes affecting train running, such as speed restrictions, engineering work or altered signalling. Notices must be read and applied before relevant duties.

A formal written account of an operational incident, submitted promptly and factually. It supports investigation, learning and any regulatory notification required.

The dedicated digital radio system used for operational voice and data communication between drivers, signallers and control. It provides reliable contact independent of public mobile networks.

The requirement that staff report for work free from illness, alcohol, drugs and excessive fatigue that could impair performance. It is a personal and legal responsibility for safety-critical roles.

The policies and personal practices controlling working hours, rest and alertness so that tiredness does not endanger safety. It includes rostering limits, rest breaks and self-reporting of fatigue.

The standards of behaviour, honesty and responsibility expected of railway staff, including adherence to rules, reporting errors and treating colleagues and passengers with respect.