Could I order a new chequebook, please? 300 mg wellbutrin sr and weight loss One thing not clear from the reports and explanations: it’s my understanding that air pressure in the brake lines of a train is used to RELEASE the brakes, not set them. Therefore, any detached car cannot roll away because its brakes will hold it. If such is the case, shutting down the last of the locomotives in that train should have locked the wheels and kept it from moving. Have I got this wrong? Or could a brake system hold pressure, without recharging, long enough for a train to roll away?