If a conductor discovers during pre-trip inspection that a car's brake hose angle cock is found closed (in the 'off' position) between two cars in the middle of the train, the effect on train braking is:

1. No effect; each car has an independent air reservoir that maintains braking for 30 minutes
2. The portion of the train behind the closed cock is cut off from the brake pipe, reducing or eliminating braking on those cars
3. Only the car immediately behind the closed cock loses braking
4. The train line will automatically compensate by pressurizing through an alternate path