AN OPTIMIZING NETWORK MODEL FOR THE CANADIAN RAILWAYS

A network model of the mainline operation of a railroad has been developed. This model predicts the optimal routing of traffic and the congestion at each yard and over each track section in the model. Input to the model is the required origin-destination flow of railcars, together with a set of physical parameters which describe each yard and the connecting track sections. Time delays in the yards are derived from queueing models of the actual system. Also, an expression has been developed which describes the over-the-road running time as a function of the traffic intensities. Output of the model gives details of the flow pattern that minimize the total car-hours required to accomplish all desired origin-destination movements, together with the delays encountered at each yard, and running times over each road section. The concept of the model is described, the component parts of this model are explained, and some potential applications in transport planning are indicated.