Water FatPounds per Gallon 8.33 7.5Gallons per Cubic Foot 7.5 7.5Pounds per Cubic Foot 62.5 56.25Standard Tank Cars for Tallow or Grease Shipments are 8,000 gallon capacity, which equals about 60,000 lbs. Approximate weight of Cracklings: 50 lbs. per cubic foot.