A simulation model for railroad line capacity analysis

The purpose of this study was to develop a model for analysing the capacity of single track railroad lines. Railroad line capacity is receiving much interest because of a continuing decline in the mileage of the United State's railroad network. The railroad industry, ship pers, and government agencies must work to ensure that the capacity of the remaining network remains adequate to serve their interests. Unfortunately, there are few models generally available for rail line capacity analysis, and much research remains to be conducted in the area.

RCM, the Rail Capacity Model, is an event oriented simulation written in the SIMSCRIPT II.5 programming language. The program simulates the movement of trains between terminals connected by a single track railroad line with passing sidings at various intervals. RCM is designed to be economical with regards to data acquisition and computer run costs. A unique feature of the model is its ability to generate, iteratively, a successive number of points in the delay function of the line modeled.

Presented in the thesis are sections describing the simulation program, its logic, input requirements, and the output provided. Accompanying the capacity model is TPCVl, a train performance calculator. This FORTRAN program, which is also documented, can be used to provide travel time data for the simulation. An example problem is outlined to demonstrate the use of the two programs.

The Rail Capacity Model should prove useful in developing line capacity estimates, especially when a quick response is necessary. Because of its generality and low operating cost, RCM fills a void in the analytic tools available to the rail planner. Hopefully, the model will aid in a greater understanding of the factors influencing line capacity.