
Notation  Definition 

 The MILP problem 
 The minimum upper bound of optimal performance of train operation 
 The optimal solution vector of optimal performance index for train operation 
 The object table of recording all LP subproblems that need to be solved 
 The optimal performance of the current relaxed LP problem 
 The optimal solution vector of the relaxed LP subproblem 
 Number of LP subproblems that have been solved 
 The maximum number of LP problems 
