Thank you for doing those - they do look rather splendid. Would it be terribly tedious of me if I were to ask if you could produce earlier livery versions of the BR Class 501 and earlier/later livery versions of the BR Class 312? When I produce new rail vehicles myself, I generally try to make sure that they have a full set of liveries that they wore during their lifetimes. Many of the older EMUs have yet to have multiple liveries, but I am hoping that that will come soon. If you need any assistance with the slightly trickier NSE livery, please do let me know.
As to the 307 - this is an interesting conundrum. Although one might think on the face of it that one could have this as a separate upgrade to the existing class 307, using the replacer to upgrade a DC EMU to an AC EMU will not work, as they would be stuck as having no appropriate electrification as soon as they had finished being replaced. I think that the best approach is simply to use this as a new livery variant of the existing 307 but keep it as an overhead DC EMU (of which there are limited numbers in any event). The same might apply to the conversion of the 501 to third rail - again, it is best to keep it as a fourth rail unit for that reason, I think.
As to the hospital - I am not so much an expert in the shading of buildings, but anti-aliasing of some sort needs to be turned on. On the other hand, the hospital doesn't need a great deal of improvement anyway, aside from the suggestions that Kieron and I have made above.