Not happy with the moulded stonework sheets, and not having had great results with clay before (except for cobbles), I've decided to experiment with foam sheet - and scribing the stones by hand - as I've seen others do this with impressive results.
The lower piece is a pizza base, the oblong piece on top centre is from a pack of foam I picked up years ago, I think it was marketed by Busch or Faller though I've not seen it since. I've looked for the blue foam others have used but can't find a local stockist. It can be found on ebay or online but can work out pricey with postage, and I fear it may get damaged. Anyway both these foams seem to work OK and I don't need a great deal.
Also shown are the implements I've tried. The right-hand and lower of the centre areas were done with a sharpened HB pencil, but I think the courses are too thick for 4mm scale. I guess mortar is an inch or two thick at most in a stone wall, so well under a millimetre. The upper centre and lower left were done with a 0.5mm propelling pencil, which I think looks better. The top left corner was done with the dental implement but I found the long point difficult to control.
So a promising test, though I suspect my stones are a bit too regular. I gave the test pieces a wash with brown acrylic. Looking at the way this has collected in the mortar courses I think I'd be better starting with a wash of grey, then dry-brushing browns on top. I've seen pastels used with great effect for stone colouring, so I might even give that a go.
I've drawn out the station building, reducing it's length by 20 mm, which I think will look better. It's marked up with measurements - as I can't draw lines all over the foam and rub them out, this will help me mark it out neatly.
The next big question is windows. Top we have a moulding by Dornplas, nice and fine but lacking detail - they don't look like sash windows. On the right is a Wills set, the lower ones of which look really nice - but only two on a fret so I don't have enough and I'd need several packs! Sadly the others, like the Dornplas ones, lack sash detail. Those lower left I picked up from a second hand stall, but I think they might be Peco. They have nice sash detail, though the mouldings are a little thick - I tried thinning one with a fine file but I'm not sure it improved it, just made it wobbly!
I've noticed some nice ones from York Modelmaking - a bit pricey though:
The other option is of course making my own. I've done it before but it's fiddly, and I'm not sure I can do better than these.