Abstract: Raising the speed of passenger trains will change the speed difference between passenger and freight trains, resulting in changes in the removal coefficient of the passenger trains and the passing capacity on a non-paralleled train diagram. The variation range of removal coefficients of raising-speed passenger trains in semi-automatic block zones on a single railway line is determined through theoretical study and simulation. The variation range is large when the number of passenger trains is small, and vice versa, and tends to decrease with the increase in the speeds of passenger trains. When the number of passenger trains is over 10 pairs, the removal coefficient is in the range of 0.8 to 1.1, being most likely between 0.9 to 1.0. It is suggested to take the removal coefficient in the range of 0.85 to 1.15.