Signalling System overview

The siganlling system at EHMR is completely computer based. At any time, the computer can be in control of all signals, points and requests.

Equally, with the use of our London Underground signalling frame, the system is able to be operated in a manual state.

Field devices

Broadly speaking, there are seven different input and output types.

Input only

• Track sections
• Sensors (for example tunnel shutter sensors, level crossing gate sensors)

Input and Output

• Request buttons - input of the button itself, output to the LED halo included.
• Points - output to set the point and input to read the current state of the point.
• Relays. Some are for input detection, some for latching outputs from the system.
• Levers - we have a signalling frame which contains up to 23 levers. Each lever has an input for Normal and Reverse, and an output to operate the electromechanical locking.

Output only

• Signals

Diagram