The Rail Tunnels is a Steam Age building.
Stages
Rail Tunnels
| Buildings | |
|---|---|
| Core buildings | Founding Chamber · Brood Chamber · Forager Trail · Twig Yard · Chapel of the Great Ant |
| Bronze Age | Fungus Garden · Lamp Forge · Seed Granary |
| Iron Age | Paperclip Forge · Bread-crumb Bakery · Barracks |
| Steam Age | Charger Boiler · Coal Pit · Rail Tunnels |
| Industrial Age | Kitchen Refinery · Plastics Works · Drainpipe Highway |
| Atomic Age | Battery Reactor · Hydroponic Garden · Alloy Foundry · Lab Annex |
| Information Age | Data Hive · Silicon Mill · Synthetic Kitchen · Satellite Mound |
| Space Age | Launch Mound · Orbital Hive · Asteroid Mine · Nutrient Vats · Solar Sails |
| Singularity | Dyson Swarm · Hive Mind · Exotic Matter Forge · Energy Conversion |