Very nice model and impresive as a first attempt.
May I suggest another version of this basic depot. I see that you have 3 loading ramps; quite unusual and this gave me another idea to give the model an different look yet respecting the basic plan (a standard architectural practice, while adapting to local specificities).
Thus, extend the loading platform from the front facade (street side) along the depot side and join it to the track side platform (and eliminating the side ramp). I would make the street side ramp as wide as the double doors (maybe it is already - could not tell from the photo), or make it larger - an architectural trick to indicate the importance of access!
Make sure that your sign is a seperate mapping, this way anyone wanting to adapt your model to a new context will have to make a small texture change. when I model a building I always think ''modularity''; therefore adaptibility.
Bravo, and do continue - I'll be glad to use it in different landscape settings.
Bernard, aka QcRail