Well, I've tried playing with templot, and sadly havent had much success with the platform modifications.

Thanks to some information on DEMU and some diagrams from the Scalefour Society I was able to confirm how wide the platform should be. Unfortunately after completing both of my planned modifications (shifting the point back and increasing the curve on the platform track) I still have not been able to get the width of the platform to comply with even the minimum standards (let alone those for a high speed line.)

Now I think I am right in saying that a secondary mainline located west of Bristol would be 100mph max speed not 125, so I guess that does mean that I can just about avoid the 100mph + requirements (this is thinking in terms of the layouts expansion rather than how it will be initially). This does help me slightly as it does allow a narrower platform (all be it not as narrow as mine would have to be.)

At the moment the platform is approximately 80mm (20ft) wide (edge to edge) at the left hand end, and approximately 100mm (25ft) at the buffer stop. This is further compounded by the extra width that is required if you want to have any platform seats (let alone having the bus stop type shelter that was planned). This has the unfortunatly affect of not only the platform being rather suspect in its accuracy should the build go ahead, but also means that actual modelling involved becomes rather dull, as there is no opportunity to add any canopies, buildings or any other detailing to the platform tops...

There are options to enable more width, none of which are really much use. The point accessing the branch platform could be moved back further increasing the distance between it and the mainline, however given its close proximity to the baseboard joint, the only way to do this would be to move it off scene, build another baseboard or to shift the whole layout along by another 12inches or so (loosing 12 inches of platform). Moving it off scene looses too much operation/building interest, building another baseboard means I may as well start again with a new plan thats designed from the outset to use that space, and having already chopped out 100mm of platform the station will start looking silly if I remove any more (particularly chopping out another 300mm!) The only other option is to use a tighter radius point (thus getting the curve finished sooner), Given that I am already using a BV8 I really dont want to go much tighter (particularly as given a BV7 wouldnt make enough of a difference it would require using a 6 which is just too tight (and looks a bit rubbish tbh).

So where does that leave the layout...

The first step is going to be research! I am going to have a hunt for a similar prototype station which has a mainline on one side of the platform and a branch on the other, with a narrow platform. If I can find a suitable prototype to use as precedence for the design then all is good and I can stop worrying about it!

If not, back to the drawing board I guess....