Swindon B


This page is intended to give you an insight into Railtrack's Integrated Electronic Control Centres, specifically Swindon B, which is what SimSig Didcot is a reproduction of.


Swindon B was built in the early 1990s as an interim control centre. It was intended that a Swindon Mega Centre would be built, which would house the control centres for most of the Western Region, from Paddington to Cornwall and Wales. Signalling being what it is, the interim 'box is still there today and is likely to remain so for several years to come! Currently it houses (and is only big enough for) one workstation, which controls from Challow to Moreton Cutting and from Oxford�  to and including Didcot Parkway.


Swindon B consists of one set of IECC equipment, which includes the following:

Signallers' workstation (SDS)

Automatic Routesetting System (ARS)

Four Solid State Interlockings (SSI)

Timetable Processor (TTP)

In addition, a few other subsystems provide interfaces and links between Swindon B and adjacent signalboxes (Swindon, Oxford, and Reading), and also information to national databases of train running information.

Other equipment, not specifically IECC, include the following:

Cab Secure Radio (CSR)

Signal�  Post Telephone concentrator/switchboard (SPT)

Train running information (TRUST)


Two signallers man the box at all times. Each works on the workstation for two hours at a time, for a shift length of 12 hours. And they're all friendly (although I wouldn't push your luck at 5am)!


Apologies for the lack of clarity in the photos. These were grabbed from a camcorder.


Signalling screens. The signaller's simplifier (a simplified version of the timetable) is the folder in the foreground.


Another view of the screens, along with essential workstation operating device (the arm). The yellow blob is a trackerball, designed to be rolled with the palm of the hand, but poorly demonstrated above! The three blue buttons are labelled N, C, and R, and these give manual points control (normal, centre (unlock), and reverse respectively). The two red buttons are the Set buttons, and the remaining two buttons Cancel buttons, each duplicated for left or right hand use.


Looking further left we have the main telephone (connected to the SPT and CSR system) in the foreground and another screen in the background. This screen allows the signaller to enter typed commands via the keyboard (middle right) and also displays alarms and messages. One final piece of equipment is the signaller re-hydration device, otherwise known as a cup of tea.


View of the Didcot Parkway area. Note how similar it looks to SimSig Didcot? The pink background to the Down Relief through platform 3 is a reminder to the signaller that there is temporary speed restriction on that track.

It's hard to see, but the signaller has put a train description in at the exit of the power station. of an empty coal train about to leave. He just had a phone call to inform him of the train description.


Now the track is occupied at the exit to the power station - the train should be ready to leave in a minute. But it can't get out - the goods loop is occupied (centre of screen) - or is it? I believe that there was a track failure that day.


One final picture: one of the detail views. This shows an enlarged picture of part of the area and can display point, signal, and track numbers on demand (it's currently only showing signal numbers).

Note also the new double junction at Didcot East.


SimSig was originally provided to Swindon B as a more professional version of SimSig (certain features were left out of the public version). I subsequently joined a small company called The Railway Engineering Company Ltd., which produces rail software. We reached an agreement where TRESIM (the professional version of SimSig) would be sold to the railway industry and SimSig rights would remain with myself for providing to the public.

Because of this, it is unlikely that any more IECC reproductions will be made available via SimSig. However, that does not mean there will not be any more SimSigs. Three new ones have already come out (Stafford, Waterloo, and Southampton), and there will be more to come in the near future we hope.


Finally, a word of thanks to all the staff at Swindon B for giving permission to release SimSig Didcot and to allow me to show you these pictures. In particular are five names:

  • Mike Miles, signaller at Swindon B, for much assistance with TRESIM and SimSig, and indeed has produced his own SimSigs (Waterloo and Stafford)
  • Gary Townsend, former signalling manager at Swindon B, for giving access to Swindon B and effectively sold TRESIM and SimSig to his managers, as well as being a good advertising tool by demonstrating TRESIM to countless people
  • Chris Burchell, former area signalling manager, for actually paying for it
  • Tony Palmer, signaller, for providing the authentic (the real) sound effects
  • Phil Ing, current signalling manager for Swindon B, for further assistance with visits.

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