Double Line Block Instruments Overview

A three-position lock and block instrument used on Eastern Railway to control train movement in sections of track.

Indicates no train in the block section and no permission given for entry.

Indicates permission for a train to enter the block section.

Indicates a train is currently occupying the block section.

Indicates block section condition for trains leaving a station. Controlled by the station master of the station ahead.

Indicates block section condition for trains approaching a station. Controlled by the station master of the current station.

A defined stretch of railway track where movement of trains is regulated to prevent collisions.

An instrument used to show the status of a section of track.

A device that changes the signal status from instruments.

A pre-determined signal to operate train commmunication.

A device used for signalling via the bell.

These sections of railway track are specifically excluded from sharing private numbers during line clearance procedures.

A signal used to gain the attention of the other station master before proceeding with line clearance procedures.

A signal indicating that a block section is free for the entering train.

A signal used by the receiving station master to confirm receipt of a signal from the sending station.

Signals sent by the station master to indicate that a train can safely depart from their station.

Bells used to signal train movements using a predefined code. They ensure safe train operation by communicating information between stations.

The initial bell signal to alert the next station that a communication is about to begin. It's like saying 'hello' on the railway.

A device that regulates train entry into a block section by granting or restricting permission. It ensures only one train occupies a block at a time.

Ensuring correct communication by verifying the identities of stations involved in a train operation. It's like confirming you're talking to the right person.

Unique codes used by stations to identify specific trains during line clearance. They're like train 'passwords' for safety.

Railway lines with high train frequency. They often don't use private numbers for line clearance due to heavy traffic.

Indicates the block section is currently occupied by a train or blocked for any reason. It's like a red light for trains.

Indicates the block section is available for a train to enter. It's like a green light for trains.

A signal sent by a station master to the next station to indicate that a train is entering their block section. This helps track the train's location.

They immediately acknowledge the signal with an exact repetition of the beats and then turn the commutator of their block instrument to the right to indicate 'Line Clear' as well.

They send an 'Attention Signal' to alert the next station about an approaching train and later send a 'Train Entering Section' signal to confirm the train's entry.

They are three-position Lock & Block instruments used on Eastern Railway to regulate train movement within specific sections of track.

The needles indicate 'Line Closed' (no train, no permission), 'Train on Line' (a train is in the section), and 'Line Clear' (permission given for entry).

It indicates the condition of the block section ahead for trains departing the station. The station master in advance controls it.

It indicates the condition of the block section behind for trains approaching the station. The station master of the current station controls it.

It means the block section is empty and no train is allowed to enter. Permission hasn't been given.

It means permission has been given to enter the block section, allowing a train to proceed.

It means a train is currently occupying the block section and no other train can enter.

The lower needle on a Block Instrument shows the condition of the Block section for trains approaching the station. It indicates whether the section is 'Line Closed', 'Line Clear', or 'Train on Line'.

The upper needle on a Block Instrument shows the condition of the Block section for trains leaving the station. The station ahead controls this needle.

The Commutator is a device that changes the signal status on Block Instruments. It's like a switch that allows you to control the signal indication on the lower needle.

When a train is occupying the Block section, the lower needle shows 'Train on Line', and the Commutator is locked in this position.

The Commutator unlocks when the train clears the station and a treadle, track circuit, or Axle Counter is activated, and the 'On' signal is given for the last signal at the station.

The Bell Plunger is used to signal the other station master using a specific code of bell signals.

The Bell Plunger must only be used for signalling trains using the prescribed code of bell signals. It's not for general communication.

The Bell Code signals ensure safe train operation by communicating information between stations. It's a standardized way to signal train movements and procedures.

The Commutator is turned immediately after the Bell Code has been signalled and before releasing the Bell Plunger. Always give the Bell Code first!

Private numbers are used to uniquely identify trains during line clearance. However, in suburban & quadruple lines, high traffic makes this inefficient. Therefore, these sections use direct communication instead.

The sequence involves sending an 'Attention Signal', exchanging station names, exchanging private numbers, giving 'Line Clear' permission and then sending an 'Attention Signal' again to the next station.

It indicates permission for a train to enter the block section. It's like getting a green light to proceed.

They repeat the signal exactly, with the same number of beats, and then turn the commutator of their block instrument to the right, indicating their section is 'Line Clear' as well.

It's a signal sent to the next station to inform them that a train is entering their block section. This helps track the train's location.

It's a signal used to gain the attention of the other station master before proceeding with line clearance procedures.

It's a device that changes the signal status on the block instrument. It's a switch that controls the display of the needle.

They return their departure signal to the 'ON' position after the train has passed the last stop signal.

They are unique codes used to identify specific trains during line clearance. They ensure a station knows which train is being referred to.

It verifies the station master's identity, ensuring communication is with the correct person.

It's a device that shows the status of a block section, indicating whether it's 'Line Closed', 'Train on Line' or 'Line Clear'.

They are designed to ensure safe train operation by preventing collisions. It's a system to manage train movements on a block section.