Well, I have slowly been working on the signal box modifications and I am reasonably happy with how it is coming along.
I received my Frosted Ultra Detail signal box door to replace the incorrect one and gave it a soak in some acetone for a couple of minutes to remove the remaining light oil that Shapeways use to remove the wax support material.
Unfortunately, you have no control with Shapeways over how the item is oriented in the 3D printer and this can impact on some surfaces leaving white and very slightly rough areas where the wax support material was attached. These areas can often be smoothed with wet ad dry paper or by scrapping with the edge of a hobby knife blade. The orientation may also leave very fine print layer lines and this was the case on the rear of the door. Most of the back of the door didn't matter except for the glass areas. I used a small 3mm wide chisel blade that I had ground from a small wood carving chisel many years ago to scrape the rear glass smooth. I then gave the glass areas a coat of clear gloss acrylic paint front and back which made it go almost fully clear, clear enough anyway to look right.
I have added the missing small vertical trim pieces on the gable end walls and used some 12mm wide modellers masking tape to mask the windows prior to spraying the Light Stone (it was exactly the right width).
I then added barge boards, fascia boards and gutters as well as spraying the walls Light Stone. I used Humbrol Matt 103 a cream to represent the Light Stone. It is slightly yellow but could be toned down with some weathering. The door was painted white as a bit of research indicated that the signal boxes didn't always seem to follow the usual stone colour schemes and often had very simple schemes. It seemed to be a bit hit and miss. The doors colours varied, sometimes all Dark Stone, sometimes Dark Stone with Mid Stone lower panel and with or without the white window trim. Later signal boxes in the pastel colour era seemed to often have a white door so I decide that this signal box was part way into that simplified scheme era.
Here is the current state with Dark Stone gutter and trim colour added. I haven't decided if I will do the vertical trim on the gable ends with the Dark Stone or not (veering towards not). Still thinking about adding some Mid Stone on the gable barge boards.
One thing I like about 3D printing is the ability to add small details such as the door handle and the bolt on the signal box door. The door handle is actually a proper knob with a thinner shank behind.
Of course there are the limitations of the 3D printing design minimums to be taken into account when drawing anything up. I should probably mention to anyone thinking about getting into 3D printing to be careful with your design as the various 3D printing companies don't use the same design minimums (usually related to wall and 'wire' thickness minimums). The prices vary considerably as well. To me Shapeways is the cheapest at the moment but there is the orientation trade off and their minimums are smaller so there can be a potential for breakage of very thin parts.
The small platforms outside the door and across the tracks are next on the list to be done.