Iron mines 1x2, Diamond mines 3x3
Is placed exclusivelly by Tunneler with Upgrade.
Diamond Tunneler, Railer, Iron Tunneler
Runs on Redstone, requires at least Rails to work. If it needs to place Powered Rails, Blocks or Redstone Torches and has none, it stops.
Tunnelers with Railers prepared behind them
Runs on Redstone, can use both MK1 and MK2 upgrades and can mine without them.
Runs on Coal and Charcoal, can use both MK1 and MK2 upgrades and can mine without them.
Railer ran into solid object and stopped to prevent failure.