return {
  -- belts
  'transport-belt',
  'fast-transport-belt',
  'express-transport-belt',
  'kr-advanced-transport-belt',
  'kr-superior-transport-belt',
  -- undergrounds
  'underground-belt',
  'fast-underground-belt',
  'express-underground-belt',
  'kr-advanced-underground-belt',
  'kr-superior-underground-belt',
  -- poles
  'small-electric-pole',
  'medium-electric-pole',
  'big-electric-pole',
  'substation',
  'kr-substation-mk2',
  -- drills
  'electric-mining-drill',
  'electric-mining-drill-2',
  'electric-mining-drill-3',
  'burner-mining-drill',
  'pumpjack',
  'kr-electric-mining-drill-mk2',
  'kr-electric-mining-drill-mk3',
  'kr-quarry-drill',
  'kr-mineral-water-pumpjack',
  -- vehicles
  'car',
  'tank',
  'kr-advanced-tank',
  'spidertron',
  -- rails
  'straight-rail',
  'curved-rail',
  'rail-signal',
  'rail-chain-signal',
  'train-stop',
  'locomotive',
  'kr-nuclear-locomotive',
  'cargo-wagon',
  'fluid-wagon',
  'artillery-wagon'
}