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Central Scotland
Mechanical Signalling
Diverting Trains
Penalty Points

Central Scotland


Mechanical Signalling

The SimSig IECC platform was not designed with mechanical signalling in mind, nevertheless it has been possible to create the essential characteristics of their operation. It should be accepted that this is just a representation and it is acknowledged that there are alternative ways it could have been done. Semaphore signals are drawn as such in the simulation.

Sections of lines that are not track circuited are shown as hollow track- you will only be able to follow the progress of the train by watching the TD or F2 menu though there is an option to display these sections as lit TCs at sim launch.

The Semaphore Signalling page gives a full description of the general principles of mechanical signalling, and you may wish to read that page in conjunction with this one. The page takes several examples from the CScot simulation.


Distant signals (D on the screen) are fully automatic in that you have no direct control over them, they will change between Green/Yellow depending on a set of programmed rules.

A distant will not change from Yellow to Green until all the section signals are off, except where a train has already passed it before the section is fully cleared. Distant will be replaced when a train reaches a trigger point, which will normally be the first (normally) displayed track circuit.

Home signals must be pulled off in the correct order, which is generally the direction of travel. Shunt routes pulling order may vary - see individual box notes . You will not be able to pull off a home if the next one is already off - in other words you must replace all the signals once a train has passed to be able to start the sequence again (as above signals will not TORR ).

In a number of areas (especially Larbert Jn), the Distant signal of one box shares a post with a home signal of another. Where sections are very short together, again around the Carmuirs triangle, there are two distant signals (an 'inner' and 'outer' distant), to ensure the driver has sufficient braking distance to stop at the home signal.

Clearing Points

Clearing points are essentially an overlap but not interlocked to the signalling and it is possible to violate them for which there will be a penalty. In most cases the clearing point is the TC immediately beyond the first Home signal.

At Stirling station it does get a bit more involved; to the South of the station the clearing point extends across several track circuits and the pointwork. However, once an UP train has come to a halt at a platform you may signal a train across the clearing point for no penalty.

If 'Mechanical Interlocking' is not selected on start-up, the simulation simply requires the clearing point to be clear and no conflicting route set. If 'Mechanical Interlocking' is selected, the simulation also requires any points within the clearing point to be set in the correct position; this will require manual intervention.

See also note for Labert Junction specific advice.

A pdf guide to clearing points can be downloaded here .

Please see also Clearing points diagrams for details of each clearing point at each box.

'Approach Released' routes

If 'Mechanical Signalling' is selected on start-up, a couple of signals can’t be pulled off for some routes until track circuits are occupied for a length of time; you will receive a message “route not ready to release” if early pulling off is attempted. Details are in the Box Notes .

If 'Mechanical Interlocking' is not selected, these routes will behave as conventional approach released from red routes.


Automatic Code Insertion (ACI) is provided at Glasgow Queen Street, Anniesland, Springburn, Cumbernauld, Falkirk Grahamston, Stirling, Alloa and Dunblane. It can be switched on/off at each location - default at start-up is OFF.

At Glasgow Queen Street TDs step to the rear berth and if ACI is on the new TD will occupy the front berth. In the case of platform 1 the rear berth is not displayed but if ACI is on the front berth will populate with the new TD. Otherwise, you must interpose the new TD as for any other platform at the front signal.

Note that ACI is an aid only, and care should be taken for any activities other than simple next workings.


All electrification is standard 25kV AC Overhead.


Prior to the EGIP program, the only electrified lines are the Up/Down Springburn from Bellgrove to Springburn platforms 3 and 4. All other lines are unwired.


Following the EGIP program, all running lines and loops in the simulation are electrified, with the following exceptions:

  • Cowlairs West Jn/Cowlairs East Jn to Anniesland/Westerton Jn
  • Larbert UGL (In reality, the loop was removed as part of the EGIP project)
  • The lines to Fouldubs Jn beyond GH9/GH11
  • The Longannet line beyond Alloa station (Electric trains may run to Alloa station only, and not to SK547)

The following sidings are electrified:

  • Eastfield Depot (all lines)
  • Cumbernauld turn back siding

All other sidings are unwired.

Diverting Trains

You will see that there are a variety of alternative routes between Polmont and Cowlairs via Greenhill Upper and Lower Junctions. The simulation is coded to allow for diversions without the need for user intervention; the timetable should automatically step up as the train passes certain trigger points. Note not every diversion possibility is coded and in some rare cases, you may still have to manually step up the timetable via F2 Options .

Falkirk High and Falkirk Grahamston are coded to be mutually recognised so a train booked a stop at one will automatically stop at the other, though the timetabled location will not update as such to reflect the alternative.

Drivers should not normally query a diversion provided the ultimate destination and intermediate station stops are still reachable. Invalid route phonecalls are coded to a minimum.

Penalty Points

"Other" penalty points can be added in the following circumstances:

  • Signalling a train in to St Rollox after giving permission for a train to enter Sim and vice versa: 10 points
  • Signalling a train in to Grangemouth Oil after giving permission for a train to enter Sim and vice versa: 10 points
  • Sending a train to St Rollox without permission: 25 points
  • Sending a train to Grangemouth Oil without permission: 25 points
  • Clearing point violations: 5 points
  • Not advising Longannet of an approaching train: 5 points
  • Violation of local box instructions at Greenhill- don't set route from GJ344 to GJ419 if GJ419 Overlap is occupied or points within are reverse: 5 points
  • Violation of the one train occupation of Grangemouth Docks and Chemical: 5 points
  • Advising Longannet of a train for Charlestown (imposes a block on one coming the other way which needs to be raised) and not sending one within 90 minutes: 25 points

Central Scotland Contents

Last edited by Steamer on 29/12/2020 at 20:32