Expansion of Canadian National Railway’s Line Capacity

In the late 1970s, traffic volumes over the next decade were predicted to double on Canadian National Railway’s already congested single track main line. As part of a plant expansion program, a transportation planning research team developed two “what-if” simulation models to evaluate the relative effect of the many factors influencing main line capacity. When used together, they predict train delay under various track and signal designs, operating methods, and traffic scenarios. We then proposed a package of cost-effective improvements for capacity expansion, which included closely spaced intermediate signals and strategically located sections of double track. These improvements, together with the application of the simulation models to plant design, have enabled CN to defer capital expenditures of over C$350 million beyond the 1980s.