The correct answer is: BCF.
BCF stands for “Brake Control Force”. It is the minimum force that must be applied to the brakes of a train in order to stop it safely. Goods trains without brake vans are required to have a BCF of at least 1000 pounds per axle. This is because they are more likely to derail than trains with brake vans.
ACF stands for “Automatic Coupler Force”. It is the minimum force that must be applied to the couplers of two trains in order to couple them together safely. ACF is typically much lower than BCF, as it is only necessary to prevent the trains from coming apart.
CCF stands for “Coupler Control Force”. It is the maximum force that is allowed to be applied to the couplers of two trains in order to prevent them from being damaged. CCF is typically much lower than ACF, as it is only necessary to prevent the trains from coming apart.
In conclusion, goods trains without brake vans shall not be run during BCF (Brake Control Force).