ST. CROIX TOWNSHIP – The last seven cars of a 52-car Montreal, Maine and Atlantic Railway train slipped off the tracks and overturned onto their sides just after midnight Saturday in this remote Aroostook County township located south of Ashland.

All seven cars were loaded with logs, with less than a carload spilling out into the nearby St. Croix Stream, according to Gaynor Ryan, vice president of human resources for the railway.

The conductor and engineer, the only crew members on board, were unharmed.

“They could feel the [rear] cars start to drag and they immediately tried to slow down, but once it starts it is hard to stop,” said Ryan, explaining that frost heaves under the track are believed to have caused the derailment.

She said the train was only going about 10 mph in that area because of springtime conditions that are typically a concern this time of year. “In general, when you have the thawing and the frost heaves you have some upheaval,” she said.

Ryan said she didn’t know when the tracks in that area were last checked, but that workers inspect the rails “all the time” and “put the slow order on in certain areas. We have section crews that work on the tracks all the time.”

Ryan said crews have been working at the site since early Saturday and she believed a crane had arrived there Sunday.

“Hopefully, by late tomorrow afternoon we’ll have the track back in service,” Ryan said Sunday evening. She said she believed the crews also were going to remove the logs from the stream.

The area where the accident occurred is located east of Route 11 and is quite remote.

“There is nothing around there,” she said, “just the train tracks and a few moose.”

Despite the remoteness of the location, the accident “put our main line out of business,” she said. Four other Montreal, Maine and Atlantic Railway trains were delayed over the weekend because of the derailment. “Fortunately we have reduced train activity on the weekend.”

Two of the log cars that derailed belonged to Irving Woodlands and were headed for St. John, New Brunswick. The other five were destined for Sappi Paper and were to be transferred at the Northern Maine Junction in Hermon.

The incident is being reported to the Federal Railroad Administration, Ryan said.