Medieval era support unit. Requires an Armory, Conscription Service, Supply Depot or Haven to produce. Can construct Roads, Railroads, Forts, Airstrips, Missile Silos, and Mountain Tunnel improvements. One of their build charges can also be used to complete 30% of a Canal, Dam or Cistern district or a Seawall building. Ignore movement penalty from all Terrians, Features and Rivers.