Hutchinson ? A sinkhole that is threatening railroad tracks in southeast Hutchinson has grown so large that plans for a long-term study were put off so workers could begin stabilizing the area.

The property owner, Burlington Northern Santa Fe railroad officials and state and local officials had decided on Friday to conduct a study to determine the composition of ground underneath the sinkhole and railroad tracks, Hutchinson Fire Chief Kim Forbes said. But the sinkhole grew about 24 feet late Sunday or Monday morning, prompting officials to postpone the study and call in work crews on Tuesday.

The sinkhole is almost 140 feet in diameter and only about 40 feet from the railroad tracks. The sinkhole was about 80 feet in diameter and 20 feet deep when it was discovered in early January.

Forbes said workers must pump a concrete slurry mixture into the coarse, sandy soil to try to stabilize soil near the tracks. Crews also may have the option of placing a wall or some other object near the sinkhole once the soil stops moving.

“Hopefully, that will slow down the advancement,” Forbes said. “If it rains, the soil probably won’t be impacted so much with the moisture.”

Kansas Geological Survey tests conducted in mid-January looked for more caverns near the former brine well under the sinkhole. Forbes said the tests were inconclusive but did find areas that will be a focus of the long-term studies.

Trains continue to run at reduced speeds while the sinkhole is studied, BNSF spokesman Steve Forsberg said.

“Anytime you have a sinkhole grow, even a little, it’s certainly something that concerns you,” Forsberg said. “If it threatens the track at all, we’ll take the appropriate precautions. For now, the subsurface under the track seems stable.”