Are your cars legal for unrestricted interchange service in North America?
Is your location served by BNSF?
Are you intending to move the cars loaded or empty?
Do you have the financial wherewithall to be able to pay the freight bill?
The carriers really prefer customers to use their own cars to carry the customers shipments - if the customer invests in the cars, the carrier doesn't have to and the customer will get a lower freight rate than if the shipments were moved in carrier owned cars.