Pairs of interconnected block instruments are used to show the status of each track between adjacent boxes worked by Absolute Block (AB). The display is set by the receiving signaller, but is shown on both instruments.
In this simulation, block bells are NOT simulated, all actions are by clicking on ‘slot’ buttons to represent the particular action.
Each pair can show 1 of 3 settings:
|Step||Action||Simulation action||Block Display|
|1a||A asks B “Is Line Clear?”||Click on green ‘C’ button|
|1b||B accepts||Click on flashing green ‘C’ button|
|1c||Line is clear, both ‘C’ buttons green|
|2a||Train enters section, A sends TOL to B||Click on red ‘O’ button|
|2b||B acknowledges||Click on flashing red ‘O’ button|
|2c||Train on Line (ToL) both ‘O’ buttons red.|
|3a||Train leaves section, B sends OOS||Clicks on white ‘N’ button|
|3b||A acknowledges OOS||Clicks on flashing white ‘N’ button|
|3c||Line is Normal /Blocked, both ‘N’ buttons white|
NOTE: In each case, the signaller only clicks on the buttons on their own panel.
In certain circumstances (e.g. train wrongly routed/signal or points failure) it may be necessary to cancel a requested route. This can only be done by the receiving signal box (Box B).
To cancel a request (override) RIGHT click on the 'OVR' button which will then start to flash white until the light steadies and "block override release given" appears in the message panel. This may take several minutes.
Box B may then RIGHT click on the white 'N' button which returns the section to normal/line blocked.
If Train on Line has already been sent, Box A section entrance signals must be cancelled/returned to normal before cancelling can be carried out by Box B.
Last edited by GeoffM on 15/09/2016 at 03:00