As proposed carbon emission standards reduce domestic coal use, the role of coal in the U.S. energy mix may be expected to decline. If such a decline were to occur, how would it affect rail traffic? Today, coal represents a major share of rail tonnage and gross revenue. While growth in other traffic?most notably, crude oil?may offset some of any potential decline in coal shipments, would it be sufficient? This paper explores trends in coal production volumes and use, rail tonnage and revenue, and the distribution of traffic origins and destinations in order to consider the impact of potential changes in future coal traffic. Rather than modeling discrete flows, it draws on historical data and forecasts maintained by the U.S. Department of Energy?s Energy Information Administration (EIA), industry studies and analyses, and background knowledge of the rail industry, specific routes and service territories, and commodity-level traffic volumes.