Improvements are built by Settlers, but can be pillaged by any land unit.
Roads
- See Roads (Civ1)
Irrigation
Mining
- See Mine (Civ1)
Railroads
Built by Settlers only, and only in squares that already contain a road. Press the Railroad key (R key). Units moving from one railroad square to another railroad square use no movement points regardless of terrain. Railroads increase food and resource production in a map square by 1/2 (rounded down). They increase trade by the same amount, but before the effects of Republic or Democracy governments.
Civilopedia
Railroads revolutionized transportation by providing a relatively cheap and fast method of moving people, raw materials, finished goods, and military units. Railroads were essential to the Industrial Revolution. Not only did they support and encourage industrial growth by dramatically reducing transport costs, but they spurred technological research on their own. Advances in locomotive technology and engineering spun off into other industries and applications. Railroads were the first great industrial corporations.
Fortress
- See Fortress (Civ1)