It all depends on rail car operator, each operators has it own pricing strategy. Some operators charge flat per mile while some charges on fixed cost. If you add another services you must have to give additional charges.
Insurance coverage against liability coverage and damage of property. It will add some more cost in your fix cost for the movement. Another most important factor to be considered is either you are likely to move your car live or dead because this fee covers the wear and tear of a normal charter.