Out of a total of 50,000 refrigerator cars,[272] about 15,000 are owned by the railroad lines. These earn, it is claimed, about 40 cents a day, while the cars owned by the Armours and other private car-lines earn or receive on the average 60 cents to $1 or more per day from the mileage payments alone. The owners of the Beef Trust cars make enormous shipments of their own, and have gained control of a vast amount of other business by offering a share of the mileage receipts and other inducements to large shippers of fruit, vegetables and dairy products, etc. With prodigious masses of traffic in their hands which they could divert to any line they chose, they have compelled the railroads to fix rates as they dictated,[273] collect their icing charges for them, delay the cars of disobedient or protesting shippers, blacklist them, shut off their credit, carry on a system of espionage upon the business of their competitors, use their power over railroads and shippers to drive their rivals out of business,[274] and even make exclusive contracts prohibiting the use of any other refrigerators on the lines of the contracting railroads. In some cases the railroads pay the car-lines commissions of 10 to 12½ percent of the freight rate in addition to the mileage on the cars loaded or empty.[275] Certain repairs on the private cars are also made by the railroads.[276] Annual passes are also granted to owners of private cars in order that their officers and agents may travel with the goods, watch the car, and look out for the care and disposal of the contents.[277] A wholesale firm which owned but one car made three members respectively president, vice-president and general manager of their little car company and got annual passes for all three members on the railroads on the strength of that one car.[278]