The recent deregulation occurred in the public railway sector in many parts of the world has increased the awareness of this sector of the need for quality service that must be oered to its customers. In this paper, we present a software system for solving and plotting the Single-Track Railway Scheduling Problem eciently and quickly. The problem is formulated as a Constraint Satisfaction Problem (CSP), which must be optimized. The solving process uses dierent stages to translate the problem into mathematical models, which are solved to optimality by means of mixed integer programming tools. The Decision Support System (DSS) we present allows the user to interactively specify the parameters of the problem, guarantees that constraints are satised and plots the optimized timetable obtained.