The rails are done with a combination of airbrush, hand painting, inks ans powders. As for prices just drop me a PM with your requests and email address and I will sort you out.
Correct about that bridge, you can find info on it and two other stone bridges by Barry Murphy’s old plant hire business in old newspapers in Waterford city library
Bren is a master at building in card etc and when he builds something you know it will last. Unfortunately not all kits or builders are as good as Bren builds and makes them. There are guys out there who won't have the same skill as Bren.
Cardboard is OK from a distance but when you are doing a building or bridge that is close to you on a layout like K is doing its hard to beat that 3d effect that the Wills gives you. Then you have the extra build quality of plastic that you don't have with cardboard in that it won't fall apart over time.
At what speed? Although Brens layout is very long you would need to measure the track to answer the above question. Also bgnworks are you talking about the actual part of the layout that is visible with scenery or the entire layout with hidden sections of running track. Check out YouTube for some of the American layouts as some of them are very big and don't forget Wonderland in Germany.
The only ones I found you need to watch are the old lima BR blue whatever type of plastic is in these they can become quite brittle. I've never had a problem with using brake fluid for stripping paint of anything else.
Playing with fire there. If the model has already been painted by hand or airbrush some break fluids can react in seconds with the paint. Also some lima factory painted stock can also react very quickly to break fluid. As I said playing with fire can write a model of in seconds brake fluid should only be used if your looking to strip the model completely of paint.