The generic hoist scheduling problem is NP-hard and arises from auto- mated manufacturing lines. In recent work using the constraint logic programming (CLP) formalism, a unifled model has been developed with the problem description and solution method separated. We provide an improved model and new prepro- cessing stages where, as before, solutions and proof of optimality are provided by a hybrid CLP{MIP algorithm. The new algorithm is more scalable and robust. We give empirical results for a range of problem classes on benchmark problems from several sources.