here goes
This is paddington towards didcot down direction
SLOUGH IECC workstation 1 and 2
paddington-stockley jct near west drayton inclusive of heathrow and all yards old oak,southall,acton etc and part of greenford branch
SLOUGH OLD BOX 2 signalling postions
westdrayton-maidenhead including windsor,marlow branch.,colnbrook branch
READING PSB 3 signalling positions
after maidenhead to reading stn including henley branch and waterloo lines to reading spur jct
reading stn to moreton near didcot all lines including berks and hants to southcote jc for basinstoke branch and to aldermaston
aldermaston to just before haywood road westbury via newbury
SWINDON B control moreton near didcot towards swindon and towards oxford but to appleford on down and from radley on the up.
hop i havent confused you go on
www.simsig.co.uk they have the signalling simulations for didcot,westbury,bristol,exeter you will see how the western region signal boxes join together
cheers
mick