Every railroad corporation operating within the state and having track scales shall maintain the scales in good order and of sufficient capacity to weigh carloads of bulk commodities transported over the railroad. The railroad shall weigh car lots of bulk commodities at the request of any owner, consignor, or consignee of such commodities, and furnish written certificates of the weights to the owner, consignor, or consignee. A reasonable charge may be made for such requested weighing.