Typically, there are a couple of ready-to-ride engines sitting on a side track, just in case.

“We like to have them ready so whenever (engineers) come over, they can go right back out,” Ferguson said.

At the other end of the barn, Craig Wilson, the general car shop foreman, Lowry and a small crew of their co-workers can get a boxcar in and out fast, too, changing wheels, brake lines, signal equipment and anything else that needs work.

They also test and monitor a range of computer chips mounted on the cars. Look above the wheels on a car and you’ll see one of the chips. From that, Lowry and other CSX employees can track cars and know what needs work and when.

Some of the work is handled inside, some on tracks just outside and some down the hill in the Acca Yard itself.

“Some of the minor stuff, whatever we can handle there, we’ll do there,” said Lowry, the car shop supervisor. “We have to keep the cars moving. It’s the same thing we’ve been doing for 150 years.”

Back across the tracks, at the edge of the yard, is the two-story command center. Hensley has an office at one end of the building, and the yardmaster and terminal trainmaster work from the other, in small rooms looking over the yard.