Simsig Swindon A & B

This sim combines Swindon A and Swindon B Didcot into one sim; it interfaces with Oxford, Reading, Westbury, Bristol and Gloucester boxes and is coded to chain with those boxes where Sims are available.

Swindon is on the high speed line from Paddington to Bristol, South Wales, and the Cotswolds. Originally SimSig Swindon covered the entire area that Swindon covers - some 60 route miles - and a separate Swindon B sim (more commonly called Didcot) covered the Didcot area. In 2008 in conjunction with the introduction of the Scrolly SimSig the decision was taken to combine the two Swindon Sims into one.

Sharing the tracks with high speed trains are coal trains between Avonmouth and Didcot, stone trains between the Mendip stone terminals and Wootton Bassett and others, freightliners from and to various parts of the country, and local passenger services.

Entry from Reading is via either the Main or relief lines and you have quite a bit of notice of approaching trains.

From the North you have Oxford station represented, again giving you more advance notice than the real box. Down from Didcot most of the track is bi-directional twin tracks, allowing for flexibility during engineering works. The Thingley Junction to Bradford Junction single line is included (8½ miles), as is the single Kemble line (12½ miles) before it re-doubles again - a serious bottleneck when delays occur.

Around Didcot you have the Freight terminal which has a number of entrances/exits. Arriving trains may be sent any of the entrances but departing trains will be presented at one other entrance as set in the timetable.

The trackwork around Swindon station is quite complex, with tracks leading to and from various depots, yards, and sidings. The station platforms are offset to one side of the through lines, meaning that down trains have to cross the Up Through line to get to a platform - which can be quite restrictive at times. With just two through platforms and one short bay, it pays to plan ahead before platforming a late- or early-running train to ensure it conflicts with as little as possible.

The Sim is divided into 3 workstations.
1 covers the interface with Bristol and Gloucester and Westbury to the Wootton Bassett area.
2 covers the Swindon Station area and the main line towards Challow.
3 coves the whole Didcot (Swindon B) area and the interface with Reading and Oxford.

• Swindon Platform 4 (default), and
  
• Swindon Parcels, epresenting the current station and the era when all stopping trains had to cross the main lines to the single island platform respectively.

Note that the entry point “Swindon Down Sidings” is only available in Parcels era.

Timetable writers will need to ensure they clearly state which option a user should select when running the timetable.

The following hot keys are enabled to centre the sim:
1 to 9 step across in equal jumps from left to right.

Press Shift + one of the following hotkeys:
T - Thingley Junction/Chippenham area
W - Wootton Bassett area
S - Swindon Area
C - Challow Area
D - Didcot Area

The user (or Server in multiplay) can block the Down Main and Down Relief lines at Moreton crossing by the insertion of a blockage code (BLOK, SHUT, *T1*, *T2* or *T3*) in the TD berths associated with Signal 901 or 903 respectively. The insertion of a blockage code will cause all trains to enter on the alternative line.

Appleford level crossing is manually controlled and is normally in the down position being raised only at the request of road users.
Stocks Lane and Causeway crossings are manned by a crossing keeper, who will lower the barriers when a route is set across the crossing. When the barriers are down, the slot will turn white and the signal will clear. The crossing keeper will raise the barriers when no routes are set across the crossing, and the track circuits across the crossing are clear.

Trains running between Oxford and Reading (and vice versa) can be routed through Didcot or via the avoiding line regardless of timetabled route. The timetable will step to the correct next location.

As well as the sim set delays dependent on the scenario selected at launch other delays occur at random to a selection of trains.

Some delays are triggered by specific code in the timetable- e.g. any train that has XC (cross country) in either the timetable descriptions e.g. ( 10:30 Glasgow to Poole XC) or train description e.g. (Class 47 + 6 XC) will be liable to be delayed entering the sim.
You may also receive phone calls from Oxford, Reading and Bristol boxes advising of early running freight and asking you whether you wish the train sent on or held back, and in the case of Reading, if you would like the train to run on another line (Main or Relief).

The main lines are bi-direcional from Foxhall Junction to the western edge of the simulation. Trains can also be sent 'wrong line' to Bristol, if the Bristol simulation is chained to Swindon. Slots are provided on the Up lines at Hullavigton and Thingley Junction to Down trains to be sent on the Up line towards Bristol’s controlled area. Similarly, Bristol can request a slot on the Down line to send an Up train on the Down line towards you.

This sim is fully ARS equipped, including, where appropriate, bi-directional running. Line coding generally follows these conventions.

• ML is Main line running in either direction on the correct lines Box to Reading.
  
• BL is Badminton line running in either direction on the correct lines Chipping Sodbury to Wootton Bassett.
  
• RL is the relief lines
  
• UL, DL, UB, DB is the line specific alternative to ML and BL and is generally used for wrong line running and some reversing moves
  
• GL goods lines/ loops as appropriate
  
• REV is used in several specific locations to indicate the train reverses.
  

Other codes are used in specific locations where there are several options and normally take the form of a signal number or a line name e.g. 'REC' at Swindon East means the train reverses on the Reception line. Hopefully these will be self explanatory.

With automatic route setting in effect, there are dangers of unwanted routes being set up prematurely.

This is particularly a problem at:

* Didcot East for trains approaching on the Down Relief Line, which call a route into Didcot when they are standing at Cholsey;

* Didcot station on the Up Main Line for trains running early but making a station call;

* Didcot North Junction for trains approaching from Oxford and requiring to cross to Didcot station

* Thingley Junction for trains coming from Westbury.

In all these cases, trains call the route earlier than might be expected, causing improper regulation, and it may be prudent to set them to non-ARS as soon as they appear on the diagram.

These trains move very slowly and need a considerable margin to complete; this is especially the case with movements from South Marston to Cocklebury.

In one timetable, a movement 6Z10 does not properly reverse at signal UM73 and it runs on towards Didcot improperly. To prevent this set signal UM73 to danger (using the emergency replacement facility, right-click on the E symbol) before the movement leaves the branch; when it stops at UM73 check whether its direction changes to “Down” (using Train List, F2) and if not it is necessary to “Abandon Timetable”, and then Reverse Direction, and set the route manually.

There is sometimes a problem signalling a movement in to Appleford Sidings if a movement is already there waiting to leave. This can arise occasionally if the driver of the train already at Appleford informs the signaller after another movement has left Didcot TC heading to Appleford. There may be no alternative to Removing one of the trains.

This needs special care as there is not much visual warning of the approach of a following passenger train. Freight trains timetabled into Hullavington loop are immediately signalled out agin by the ARS, which must be suppressed. When a freight train is approaching Hullavington, (or is in the loop and about to leave) the expected time of the next Up passenger train needs to be ascertained. The simplifier (F8, remember to select “All Platforms”) is a start for this, but does not include passenger trains that are running late but which would, if on time, have already passed. To check them, you need to check the Incident List (teleprinter symbol next to the telephone) and look for relevant up Badminton Line trains – 1LXX identities – that are running late and compare them with the timetable (F4) which shows you the entry time at Chipping Sodbury. This is all exceedingly laborious but there seems to be no simpler method.

Note that in one timetable, 6A12 is too long to be accommodated in Hullavington loop, and once it has entered the area will need to run to Wootton Basset loop.

Didcot

• P1 319m
• P2 326m
• P3 221m (PP-A)
• P4 220m (PP-A)
• P5 240m (PP-C)

Swindon

• P1 261m (PP-C/PF)
• P2 80m (PP)
• P3 282m (PP-C/PF)
• P4 300m

Chippenham

• P1 239m
• P2 239m

• Didcot UGL 410m (PF)
• Milton DGL 1447m (PF)
• Highworth UGL 570m (PF)
• Highworth DRS 512m (PF)
• Wootton Bassett Jn UGL 570m (PF)
• Hullavington DGL 559m (PF)
• Hullavington UGL 468m (PF)

• You need to request permission to send trains to Didcot Power Station. You will be told which line to use which may differ from the one indicated in the timetable. In such cases you will get an “off planned path” message which is simply stating the obvious and you are not scored on receiving these messages. But you will be scored if you don't follow instructions.
• You will receive phone calls from various sidings and yards requesting permission to enter Sim.
• Appleford crossing will close automatically on Sim launch
• Oxford line entry point is now Kennington Junction- old timetables will still work but times will be around 2.5 mins out
• Early running trains from Reading will be notified and you will have the option to instruct entry by a the alternate line

Signal Number Plan (click the picture, then click again to read):

Route Tables

*Fringe box, signals not controlled in this sim.

Non-prefixed signals are controlled by Swindon A (SN), except those on Workstation 3, which are controlled by Swindon B (SB).

Geoff Mayo and Mike Miles built the original Sims.
Peter Bennet combined the sims.
Clive Feather and Kurt Sickelmore assisted with data and code programming.
Daan Krantz, Andy Brown, Howard Potter, Tony Hutchins, James Roberts, Darren Towler, Darren Goble, Jamie Warwick, Chris Law and Chris Lord for endless testing of the Sim.
Management and Staff in both boxes.