Here's my texture for the low-poly model:
It's messy, but ok for the distance that the low poly model will be seen at.
The actual texture will be much lower resolution of course (as it's got to be 256 by 256 pixels)...
Which will make it this small:
<<<<<EDIT: I've now improved teh texture slightly, and have posted the updated version later in this blog.>>>>>
(...Turns out I did already use "rolling stock" as a title... oh well.)