Welcome to Ludendorff city! This railroad station is intended to be added in the bigger Ludendorff mod as an addon to make it richer. Unfortunately this is quite impossible because it contains appr. 1200 props so until the limit won't be changed it has to be a stand-alone.
To get Ludendorff mod visit:
http://www.gtainside.com/en/gta5/maps/87560-ludendorff-mod-0-4