A long hot summer in the US has increased demand for electricity, and demand for natural gas, whose price has increased from $2 to $3 per million BTU's. This increase in the price of a close substitute has increased the demand for coal. This is a shift in demand.
In the graph above, we see a slight increase in quantity, which represents a dramatic change form the downward trend in demand. As a result, railroad stocks are up as railroads and barges are the only way to move coal.