The question was what if the line was blocked at Shepherd's Bush :P Via the NLL is the logical route. If Willesden is blocked, again go for the NLL at Kew, then take the Dudding Hill line to join the WCML at Harlesden.
If there was a problem between Harlesden and Rugby the best bet would be to take the NLL and Dudding Hill to join the Chiltern ML at Neasden, and switch back to the WCML at Bordesley or via Kenilworth and Bedworth. That would be a lot shorter than via Didcot (and has less freight to path around).
Another option would be WCML to Willesden No. 7 Jun (single line that branches off just after Harlesden DC station), Action Wells Jun, through Acton Central/South Acton NLL stations, Kew East-New Kew Juns, Chiswick station, Barnes Station, Clapham Junction..... or even more esoteric Acton Wells Jun, Poplar Jun, onto the GWML down relief, down main, reverse at Reading, and thence via Bracknell.
Note - I'm hoping that three unelectrified sections of line in West London will be wired as part of the GWML wiring: Willesden Number 7 to Acton Wells Jun which is one mile (where it brieftly joins with the OLE of the NLL), and Acton Wells Jun to Poplar Jun which is 0.7 mile (these two bits I've made reference to in the diversionary route above) and Willesden West London Jun to Acton Wells Jun (again one mile) which would be needed to get an electric ECS from Waterloo to Wembley depot (but see lower).
If electric hauled passenger services were to become a reality as described, then the triangle of lines from South Action to Brentford and Kew Bridge ought to be done as a little infill third rail scheme aswell (less than 3 miles).
Can I first of all say that eagle and MRC247 have the patience of saints. Some good debate in this thread has been diluted by.... well whatever you want to call it, the mods have dealt so I won't say any more, apart from to share the frustrations of others.
A few random points from me if I may:
-the sleepers (both) have suffered from years of "not really being bothered" treatment from Intercity and First. That First Rail has never produced any joint marketing of the services speaks volumes.
-the savings offered by joint management must be worth consideration, though this would effectively be a smaller TOC than Island line, so it may not produce any saving at all. That said - tagging all the sleepers onto FGW is no more bizarre than them being tagged onto a commuter operation in Glasgow. This would not necessarily necessitate a change of termini for either - for example both Old Oak and Willesden are accessible from Pad Eus and Waterloo with max of one reversal.
-agree that cleaning and stabling could easily be done in platforms at Waterloo International. With cyclical working and identical formations, stock could quite easily be rotated (as already said) so that sunday night it is the up lowland, monday night down riviera, tuesday night up riviera, wed night down highland, thu night up highland, fri night down lowland - and the sets that do lowland being the ones that receive their A exam at Polmedie during that day. If there were seven identical rakes (complicated by the fort william, granted) then each rake could get one work day a week off for B exams when needed. This is just an example though.
-re Old Oak, is it still on the cards that FGW are going to transfer lock stock and Barrel into North Pole?
-it does seem likely that there will be disruption at Euston as it is remodelled, so moving the sleepers away from there (at least temporarily) makes sense.
-I don't see why both p1 and p2 at Waterloo would need to close. If p1 was closed and lifted, then (as already said) p2 could be extended southwards to the point where the track out of p2 becomes the down main slow (i.e. the eastern most line) - this meaning that the required 10 or 12 coach length should be perfectly feasible.
-regarding the route into Waterloo, as far as I can see this would not share track with any SWT services at any point. From Kensington Olympia, all would pass through Imperial Wharf station, shepcote lane curve, then join the Windsor Reversible right the way to the eurostar platforms. Looking at both peaks, I could only find one train which used this line (looking at platform 1 at Vauxhall, and know from experience it is rarely used).
-on the subject of the lowland, then to avoid any uncoupling, one thought is for the whole train to go into Glasgow Central (with an early bird stop around 6am for those who want it), then the whole train to Motherwell, Edinburgh, then back to Glasgow for those who prefer a couple of extra hours in bed, thence to Polmadie. Replace the two Glasgow calls for the two Edinburgh calls (and stabling on Craigentinny) if this is considered a better way to cater to a business market who may want to be off by 7am and a tourist market who may want to stay asleep until 9am.
-regarding the highland - before I suggest that Fort William should be cut as uneconomic, and the aberdeen and inverness should run as one train London-Stirling-Perth-Dundee-Aberdeen-Inverness, does anyone actually have any usage figures for this service? Either something official, or their own feedback from a previous trip?
