GRIP▸ is Guide to Railway Investment Projects, which has the stages from 1 (basic aim of project) to 8 (completion).
For details, see
http://www.networkrail.co.uk/aspx/4171.aspxThe epic Arup document is online at
http://www.rail-reg.gov.uk/upload/pdf/pr08-arupenh-040608.pdf - relevant bit is pages 99-102, also mentioning Swindon-Kemble.
I was slightly dubious about
NR» 's ^50m-plus figure anyway, since one of their people told me it was more like ^74m to ^92m the day they unveiled the proposals. How you square the
ORR» 's ^40 million-odd estimate in their response to the Network Rail Strategic Business Plan with what their own consultants appear to be telling them is an interesting one. Did they by any chance just take Network Rail's initial figure and knock a bit off?
From what Arup say, it appears they and Network Rail are still trying to get a handle on exactly what work is involved, which may explain much of the discrepancy.
But it doesn't inspire confidence in Arup's figures when their diagram omits Shipton station and they put in things like the following: "Provide a turn back facility in the London direction at Moreton-in-Marsh to allow trains to terminate and turn back to Oxford" which suggests they haven't even looked at a track diagram, never mind visited Moreton, where they would find just such a facility already exists, able to handle an 2+8
HST▸ , which is used every morning by the first train of the day to London - unless someone wants to move the reversing point from dead-straight track south of the station on to the sharp curve to the north, which would seem a pointless piece of expenditure if that is the idea.
And bear in mind the cost of redoubling work varied wildly on the Chiltern Line. The first stage from Princes Risborough to Bicester came in at ^1m a mile but Bicester to Aynho was ^8m a mile in 2002, which would put 20 miles of the Cotswold Line up at ^160m!
An interesting footnote is that the diagram of revised track layouts includes "passive provision" at Honeybourne for
GWR▸ steam trains from Broadway to use the reverse face of the reopened island platform.