Usually what happens is that the tire(s) cause the glad hands on the brake pipe hoses to come apart between one or more cars. It sounds like the conductor may have been a little confused, however if he had to cut out a control valve, then the break was in piping between the control valve and the rest of the air brake apparatus on the car, a very rare occurrence. Two cars in succession may not be cut out -- one of them has to be set out.