Have 4 Advanced Docks and 12 Reloading Stations working at the same time
You only need the standard reloading station to claim this achievement, which can be done easily if you have a total of 12 steam cores and enough steel and wood to build three stations on each Advanced Dock.
Less-than-honest tip: If you have 12 steam cores but they are tied up in other buildings, you can always save your game, dismantle a few, build everything for the achievement, and reload your save.