Many railroad lines are approaching the limits of practical capacity, and estimated future demand is projected to increase 84% by 2035. Therefore, identifying a good multiyear capacity expansion plan has become a particularly timely and important objective for railroads. An enhanced parametric capacity evaluation tool has been developed to assist railroad companies in capacity expansion projects. This evaluation tool is built on the Canadian National Railway Company parametric model by incorporating enumeration, cost estimation, and impact analysis modules. Based on the subdivision characteristics, estimated future demand, and available budget, the proposed tool will automatically generate possible expansion alternatives, compute line capacity and investment costs, and evaluate their impact. For a particular subdivision, there are two outputs from this decision support tool: a plot that depicts the delay–volume relationship for each alternative and an impact and benefit table that shows the impact of the future demand on the subdivision with different upgrading alternatives. The decision support tool is highly beneficial for budget management of North American railroads.