That's my era 1970'2 onwards Worked 1974 till 1980's on the railways. There were still some Green about to. I would like to see something over the East Coast Mainline. Kings Cross to Hitchin, also including the Hertford Loop
In typical fashion for me, the GEML, okay I'd probably prefer that later on in the sectorised era but blue will still do me just fine, anything heritage and anything East Anglian will be a win in my book.
A network built around Cardiff Canton or Newport for me. Loads of steel and oil freight, intercity and regional loco hauled and some really rubbish DMUs on the valley lines