Better take a look at the article. It says,
"The C&O test report and correspondence between C&O and PRR substantiate Dr. Huddleston's revision. The stop at Cotton Hill was recorded at 30 seconds, with no qualifying remarks. The train made a routine stop, then proceeded on its way east."
I think that answers the question. 30 seconds is a mighty short time to get a helper from Handley, about 18-19 miles away.
The article also says,
"At Waynesboro, 5539 failed to start its train of 13 cars and 1,098 tons....."
That's about 200 miles east of Cotton Hill, IIRC.