I should have mentioned that you also have a lot of options to make Propper props have better lighting.
Firstly, you can give them a custom UV and enable lightmapping, but that's a lot of work.
Second, you can cut them up a bunch so they have more vertices (and therefore prettier vertex lighting).
With your prop in particular, I'd bet that if you make 4-8 horizontal cuts spaced by 2 units each just below the railbridge part (where shadows are most commonly being cast), and 2-4 vertical cuts next to each beam, you'd get much better lighting without actually increasing the polycount much at all.
You can also cut up the beams more, since right now these parts on the inside are receiving light bleed through the wall:
This is presumably because the inside faces of the side of the beam are all one face, so the vertex lighting is creating a gradient from one side, where there is light, to the other side, giving the illusion of light where there is none.
Hopefully that makes
any sense, I feel that I've explained it poorly.