SimSig Royston

Manual - version 4.1

Last modified: 2018-07-23

Table of Contents

Geographical Summary
    Electric Traction
    Down Sidings area
    Platform 1 stop sign
    Platform lengths
    Depot, yard, and siding capacities
Startup options
Hot keys
Train Service
Timetable Locations
Hints and Tips
Splash screen photos
Known problems


SimSig Royston was the first simulation I ever wrote. This page describes version 4.1; version 4.0 was a major rewrite to work with the Loader and to take account of new information that I have obtained, while 4.1 adds further realism.

In real life, Royston is part of the area covered by King's Cross PSB. However, technical reasons meant that the original SimSig King's Cross wasn't able to cover it and instead ended at Baldock. I therefore wrote SimSig Royston to cover the missing section, as a good starter simulation for people new to SimSig, and as a good starter simulation for me to learn the techniques of writing simulations.

The area covered by SimSig Royston is also part of SimSig Cambridge.


As ever, my thanks to Geoff and Mike for teaching me how to write simulations, to all the people who provided information, and to the beta testers.


SimSig Royston simulates the Royston area in about 1980, shortly after the transfer to King's Cross PSB in 1976. The Cattle and Corn Mill Sidings have already been removed, but the complex of sidings and yards on the down side remain untouched. However, the main lines in the simulation are electrified throughout even though in real life the electrification was only extended from Royston to Cambridge in 1988. Speed limits are those in use in 2012.

Unlike previous releases of SimSig Royston, all signals have their appropriate prefix (K or CA).

Geographical Summary

The area covered by SimSig Royston runs from a point between Baldock and Ashwell & Morden at the south-west end to just past Meldreth station at the north-east end. The whole simulation represents about 10 miles of line, but all the activity takes place in the mile around Royston station.

The Up direction is towards Baldock and the Down direction towards Cambridge. Which is leftwards and which is rightwards depends on the option chosen at startup. The actual line runs roughly north-east (Down) to south-west (Up), though with a curve just north-east of Royston station meaning the Cambridge end is more northerly and the Baldock end more westerly.

Outside the Royston area the line is simple double track with normal left-hand running. Both platforms at Royston are bidirectional with crossovers at each end. There is an extensive network of sidings and yards, mostly unsignalled, on the down side and a single siding on the up side. Two automatic level crossings are also monitored by the signaller.


The general speed limit is 80 mph on the Baldock side of Royston, 90 mph on the Cambridge side, and 50 mph (with easements for EMUs) through the station itself. The two trailing crossovers are 30 mph and the two facing ones 25 mph. Yards and sidings are normally 10 mph.

The EMU speed class is recognized by the simulation for the easements; other speed classes may be set but will be ignored.

Electric Traction

The two running lines, the crossovers between them, and the Up Siding are equipped with AC overhead. All the sidings and yards on the Down side are unwired.

Down Sidings area

The area on the down side on the Baldock side of the station is the most complex part of the simulation. There is a third track, known as the Down Loop for most of its length but the Down Siding at one end. Branching off it are four separate goods yards; starting at the station end:

Dalgety Siding is a single track and therefore trains entering it will stay there. The other three each have two sidings within them and are therefore simulated as exit and entrance points. However, the simulation keeps track of the total occupancy of each yard and won't allow trains to enter when there isn't room or non-existent trains to exit.

The sidings are mostly unsignalled and non-track-circuited, so trains can't be controlled directly by the signaller. Instead there is a shunter who must be telephoned with instructions.

When a train for one of the yards arrives, it must be signalled on to the Down Loop in the normal way. Use one of the following combinations of signals:

Before doing so, however, telephone the shunter to tell them where the train is actually going. They will then move the hand points accordingly. There is also an option (see below) to have the shunter recognize the train from the timetable and set them without being asked.

When a train is ready to leave the Freight Depot or the Grain Siding, the shunter will telephone for permission to depart. If granted, the train will enter the simulation and, if possible, proceed to K249 or K224 signal. If the points can't be set for some reason, the train will just sit at the yard exit until you phone the shunter and tell them to let the train out. Similarly, when a train is ready to leave the Down Siding towards K249 or Dalgety Siding or the Down Loop towards K244, you must phone the shunter to get the hand points set and wave the train forward. Once at K249 or K244 the train will phone if delayed in the normal way.

Because of its location, Sheriff's Siding is more complicated; trains need to be reversed in the Down Siding on their way in or out (this reversal should be included in the train's timetable). So the steps required to get a train into Sheriff's are:

  1. Phone the shunter and say that there is a train for the Down Siding (or rely on the shunter if the relevant option has been chosen).
  2. Signal the train from K246 to the Down Siding.
  3. Telephone the shunter to let the train out of the Down Siding to K249.
  4. When the train arrives at K249, telephone the shunter again to say that there is a train for Sheriff's (or rely on the relevant option).
  5. Click on K249 and then K253 to set the route; only the first section of the route should light up (if both sections light up, the shunter has set the points wrongly and you're about to be in a mess).
Similar manoeveurs are required to get a train out.

Be warned that the shunter is a bit bolshie and won't use their initiative; they will only set the points or wave trains around when told to. In particular, they'll quite happily let you signal a train forward and send it to the wrong place (but, again, see the options below).

The set of 8 train berths near these yards is the "scratchpad". See the startup options for details of how this works.

Warning: the location called "Sheriff's Siding" in previous versions of SimSig Royston turned out to be the Grain siding. This will affect old timetables; see below for more details.

Platform 1 stop sign

Until the line towards Cambridge was electrified, the service was split into two with EMUs from London terminating at one end of platform 1 and DMUs from Cambridge terminating at the other end; passengers would then walk between them (or run if their arriving train was late). Rather than having full signalling for this, there were neon "STOP HERE" signs facing each ways suspended from opposite sides of the road bridge crossing the centre of the platform.

The signs are shown as black symbols on platform 1; when lit, the indication shows white. Next to them are exit arrows; a route can be set up to this arrow in the same way as up to the exit signal and either the main or subsidiary aspect will clear as appropriate. Trains will proceed up to the sign and stop there. The sign will go out when the rest of the route times out after the train has been in the platform for two minutes; a train can then be signalled in (either to the sign or up to the other train to join) from the other end.

Drivers are instructed not to pass the sign, even after it goes out, until the signal at the far end of the station clears.

Platform lengths

Platform 1 is 247 metres long and platform 2 is 169 metres. At the Up end the signals are at the end of the platform. At the Down end, signal K981 is 94 metres beyond the end of platform 2 and signal K983 is 116 metres beyond the end of platform 1. In each case the two track circuits exactly cover the platform; the boundary between them is 183 metres from K980 and 116 metres from K978.

These lengths are exact and do not allow for stopping space.

Depot, yard, and siding capacities

The following yards use depot capacity control:

Depot or yardCapacityMaximum
Freight Depot240 m140 m
Sheriff's Siding250 m180 m
Grain Siding400 m300 m

Other capacities are:

Down Loop (clear of Freight Depot point)103 m
Dalgety Siding220 m
Down Siding140 m
Up Siding220 m


The scenarios are self-evident.

Startup options

The following options are available at startup.

Scale of problems
This allows you to select how likely problems and failures are to occur.
Random TSRs
If selected, one or more TSRs will be installed at random.
Train Operated Route Release
If selected, TORR will be in effect. TORR is not installed on King's Cross panel - routes must be explicitly cancelled behind each train - but beginners may find it easier to play with TORR on.
Timed approach control
If selected, signals will have approach locking (usually of 2 minutes) even when no trains are approaching. This is how King's Cross panel actually works, but beginners may find it easier to play with this turned off.
Long routes
If selected, it is possible to set consecutive routes with a single action. For example, clicking on K986 and then K978 will set the route into platform 2 in a single go rather than requiring K982 to be clicked on twice on the way. All possible sets of consecutive main routes may be set. Long routes will only set if all the relevant routes are available and will not make use of warning or calling-on routes. Setting routes from K975 or K977 to CA103 will use platform 2 if possible but will try platform 1 if not; similarly K986 to K976 will prefer platform 1 but will try platform 2.
Active scratchpad
Normally the 8 berths of the "scratchpad" are just for the player's use. Descriptions can be entered there and removed without affecting the rest of the simulation. However, if this option is selected then these berths become part of the train describer and train identities will enter and leave them in the normal way (the real King's Cross panel doesn't have any TD berths in this area). Descriptions can still be interposed or removed by hand. In this mode the two "spare" berths in the scratchpad are assigned to K249 and K244 signals. Note that as a train moves along the Down Loop there may be a short delay between an indication leaving one berth and entering another. For example, if a train proceeds from K246 to the Down Siding, its description will disappear when it passes K246 but only appear in the scratchpad as it passes behind K249.
Shunter knows timetable
If this option is set, the shunter will set the points in the yard according to the timetables of trains. However, they will still not wave trains forward without specific instructions. A telephoned instruction to set the points will override the timetable for the next train in the relevant direction (e.g. an instruction to set them for the Grain Siding will apply to the next train entering in the Up direction from K246 or along the Down Loop from K244, but trains towards Dalgety siding from K977 or K245 will still be routed according to the timetable). All telephoned instructions cancel all previous ones; the shunter will not remember two sets of instructions at the same time. Instructions can also be cancelled with a specific call.
Screen layout
There are three possible screen layouts. All have exactly the same functionality and only differ in appearance.
Stacked signals
The signals at the Cambridge end of the station are back-to-back in real life. By default they are shown using the SimSig standard layout rules, which leaves a space between them. Ticking this box gives you the arrangement actually used on King's Cross PSB panel.

Hot keys

There are no hot keys.


SimSig Royston can be chained with SimSig King's Cross. For chaining purposes it is treated as "Cambridge".

Train Service

The supplied timetable is based on the workings of Summer 2003 plus a couple of imaginary goods trains.

The normal train describer 1A23 system is used. As well as the normal regional and inter-regional ones, the following local route letters are used on the line:

CKing's Cross to/from Cambridge
RTrains originating from or terminating at Royston
TKing's Cross to/from Ely and King's Lynn

In 2003 the passenger service was operated by Prism Rail (a part of National Express since 2000) under the name "West Anglia Great Northern". Because of franchise changes, in 2004 the service was renamed "WAGN". In 2006 the route was moved to the Thameslink franchise operated by First Capital Connect.

The service consists of a mixture of fast and stopping trains running at least as far as Cambridge, though a few services start at Royston in the early morning. The "Cambridge Cruiser" services pass through the station without stopping. Trains are operated by a mixture of class 317 and class 365 EMUs, though class 313 can be found on the Royston originators.

Before electrification to Cambridge in 1988, there was a service of class 312 EMUs between King's Cross and Royston and a rather less frequent service of DMUs from there to Cambridge. In general the London trains turned round in platform 1 if connecting to a Cambridge train and platform 2 if not.

Timetable Locations

This section lists the internal codes (which in many cases are TIPLOC codes) for the timetable locations in the simulation, and also provides a brief description of the less-obvious locations. These codes are used when using the timetable converter.

When a train enters the simulation a different code - an entry point code - is used. These codes are shown in italics following a » symbol. In general, the entry location should not be the first location in the train's timetable as well.

ASHWELCAshwell & Morden
K249GGrain siding » EROY249
K249SRoyston Down Siding
K977245Royston K977/245 (reverse); both tracks; use for reversals only
K247Royston Up Siding
ROYSSHRSherriff's siding » EROYSHR
K246Royston K246 (reverse); use for reversals only
K244DDalgety siding
K244FRoyston Freight Depot » EROY244
ROYSLPRoyston Down Loop

Warning: timetables built with previous versions of SimSig Royston will have problems with trains using Sheriff's siding and the Down Loop:

Hints and Tips

Splash screen photos

A brief description of the various "splash screen" photographs. All were taken in March 2005.

The view towards London from the end of platform 2. K978 and the crossover into the down loop are in the foreground, with K980 visible at the end of platform 1.
A view along the station from under the footbridge. The "STOP HERE" signs were mounted on the right hand wall of the road bridge in the middle distance.
Unit 365 511 departs from platform 1. The station end of the Down Loop and K253 are clearly visible, with the back of K978 immediately above the speed limit signs.
Unit 365 511 passes signals K246 and K244. The running line crossovers and those to and from the Down Loop are visible, as are the remnants of the Dalgety Siding and Freight Depot.

Known problems

[Mantis 19785] A train description should normally step directly from signal K977 to K980 or K983. It should not normally step to K246.

[Mantis 19856] There should be a single train description berth shared between signals K245 and K976.

[Mantis 20002] On certain routes the signal should revert to red when the second track circuit in the route is occupied. These signals currently revert to red when the first track circuit is occupied.