The £14m figure came from the 3rd or 4th reply to the thread on page 1.
Why it's into the millions is what escapes me. Naturally NR will need 536 consultants, each charging 3 times the cost of the actual work, but in principle this should be a doddle. Throw in a set of points, stop board on entry, stop board with PL/shunt disk as appropriate and a phone (or just use GSMR) for departure, motorised trap points before access to mainline, bish bash bosh, that's your lot.
(Yes I know I'm being facetious please no one take this seriously). I would, however, love to see/hear a genuine breakdown of cost though.
It's impossible to give a genuine breakdown of costs without somebody sitting down and doing the work, which they would then need to charge the project for!
The project would need to pay for everything, from Surveys to the design work to the line block to the rails to the person who has to update each and every document to include all the changes for future maintenance/enhancements. As a new project it will need to meet modern standards and be assured to that level. It takes time to gather the information, work out solutions and come up with a final design, then it has to be checked by drivers and signallers to make sure the signals can be seen and the signallers can set the routes. Once that's been done, the line will need to be blocked and the signalling altered when the points go in, and everything tested to make sure it all works as it should. Then there's clearup and final fettling, and meanwhile somebody's been going through several hundred documents to make sure everything is up to date and accurate.
NR has it's own in-house consultants, and they cost the company a lot less than going through private sector companies. A passenger line cannot be protected by a stop board, it needs an aspect that can be proved, and trap points need to be designed so that a derail train is not sent into a lorry loading bay!
Just because you can't work out how something costs that much doesn't mean people are lying when they quote figures of £Xm.