Determining the Causes of Train Delay

Class 1 railroads are expected to face increasing capacity constraints due to long-term projections of growth in both freight and passenger traffic. To prepare for this growth and to strategically determine the best capacity expansion projects the Class 1 railroads make extensive use of a simulation tool known as Rail Traffic Controller (RTC). This tool can be used to estimate the capacity of existing or propose track and signal configurations. One of the primary outputs of these analyses are estimates of train delay. Delay is the extra time it takes a train to operate on a route due to conflicts with other traffic. Reduction in delay is often used by the railroads to calculate the benefit of a project or operational change. However the specific factors that cause these delays are not well understood. We used RTC to categorize and quantify the delay due to different types of conflicts and operational causes. The conflicts considered were meets, passes, mainline restrictions and entry delay. The operational causes considered were the delays due to acceleration, braking, reduced speed and dwell time. The results were studied for trends and offer a better understanding of the principal factors that contribute to train delay. With delay being used as the primary metric to select projects, understanding the leading causes of delay is important to plan capacity more effectively and economically. This work provides insight into the outputs railroads use for their decision making and potentially allows planners to more effectively choose specific alternatives that will provide the greatest benefit.