it is best allowed to generate the anticipated values of the ros and possibly other variables for each of a few consecutive detection times in a normal railway operation as mentioned earlier the faulty ros variables for t that are those ros variables with a discrepancy for t are assumed to continue being faulty and all the other variables are assumed to be initially normal in the generation of the pessimistically anticipated values which is based on the master train schedule for t and initialized with the measured values of the ros and possibly other variables for t some guidelines for the generation of the pessimistically anticipated values are suggested in the following 1 the pessimistically anticipated value of a faulty discrete ros variable e g signal or switch for time s u2267 t is set equal to its measured value for time t the pessimistically anticipated value of a faulty continuous ros variable other than the locations and speeds of trains for time s is set equal to the predicted value of the faulty continuous ros variable for s obtained by the railway operation predictor using the master train schedule for time t the pessimistically anticipated values of the faulty discrete ros variables up to and including s and the measured values of the faulty continuous ros variables for time t 2 in accordance with the pessimistically anticipated values of the faulty ros variables e g signals and switches for time t the railway operation predictor uses the master train schedule for time t and the measured values of the train locations speeds and or accelerations for t to predict these continuous variables for the time s the predicted values are used as the pessimistically anticipated values of these train.