The file is in 8.5x11 pieces in PDF form.

Make sure to deselect "fit to page" so it prints 1:1. 

There are some letters around the base so you could line up the 
walls reasonably.  Cut the upper edge of the first floor walls 
between "b" and "f" and between "h" and "i" but not between "f"
and "g" or "g" and "h".  

After you assemble the main walls and put on the first floor roof,
it will be obvious where the "dormer" goes.  The freight platform 
just slips around the end of the freight room.  The stairs are just 
ramps with lines on them...

Included is a JPG of the depot in its heyday.  There's obviously a 
lot of detail I left off the paper version, but again it was 
completed to check the overall proportions of the drawing.

The walls were the SP mustardy yellow, and all the trim was the 
maroon-brown.  Roof shingles were probably gray-brown.