THE MIT SERVICE PLANNING MODEL. STUDIES IN RAILROAD OPERATIONS AND ECONOMICS. VOLUME 31

The Service Planning Model provides a low cost, realistic way of evaluating alternative operating plans. This report is a functional description of the model, which has been used successfully in studies with the Boston & Maine and the Santa Fe railroads to help evaluate alternative operating plans and establish service standards. The model's major asset is its ability to produce detailed customer service information, including O-D trip time distributions. These are developed using probabilistic train connection standards rather than cut-offs. By summarizing operating costs and estimating car utilization costs, the model helps in balancing car costs and the costs of train and yard operations. The principal inputs to the model are train schedules, blocking information, the network description, and probabilistic train connection standards. The model uses this information, with logic similar to that used in car scheduling, to predict O-D and yard time distributions. Rather than simulating the movement of thousands of cars through a complex network, the model uses analytic techniques to estimate trip times. As a result, the model requires much less time for data preparation and much less computer expense per run (currently in the range of $50 to $100 per run). This means that the model can be used frequently in many kinds of studies.