Not all the news about coal is negative.

The Association of American Railroads reported Wednesday that U.S. rail traffic for March of 2.6 million carloads was up 5.5 percent or 134,363 carloads and intermodal units over March 2016. Coal traffic was up 19 percent or 63,846 carloads; crushed stone, gravel, and sand, were up 12.5 percent or 13,154 carloads; and grain, up 10.6 percent or 11,336 carloads.

Commodities that saw declines in March 2017 from March 2016 included: motor vehicles and parts, down 5.3 percent or 4,999 carloads; petroleum and petroleum products, down 8.1 percent or 4,382 carloads; and chemicals, down 1.3 percent or 2,113 carloads.

The increase for coal is relative to abysmal lows reached a year ago, said John Gray, the association's senior vice president of policy and economics.

"Despite recent increases, in absolute terms, rail coal volumes are much lower than they were even a few years ago, and rail crude oil volumes are roughly half what they were a couple of years ago," he said in a statement. "On the other hand, this was the best March ever for carloads of crushed stone, sand, and gravel, and it was the best March for grain since 2008."

U.S. traffic for the first quarter of 2017 was 6.7 million carloads and intermodal units, an increase of 3.5 percent compared to last year.