ELLENDALE — Union Pacific crews continued working Monday to clear 16 rail cars from the site about a half mile south of Ellendale where a train derailed Friday.

“This is a lengthy process that requires splitting each car into sections before removal,” said Raquel Espinoza, corporate communications director for Union Pacific Railroad. “We expect the process will be completed by mid-December. We are committed to restoring the area and appreciate the community’s patience as we work through this process.”

The cause of the derailment remains under investigation.

One rail car in the 146-car train was reportedly punctured during the derailment, leaking liquid petroleum gas and leading to the evacuation of the nearly 700-resident community and other residents within one mile of the train on Friday morning.

Nearly all evacuated residents had returned home by Friday afternoon, according to the railroad company.

Union Pacific officials removed the remaining liquid petroleum on Saturday from the punctured rail car and one other car using a vent and burn method. The liquid was slated to be released into a contained pit and then burned over the course of four to eight hours.

The train was reportedly hauling mixed freight from South St. Paul to North Platte, Nebraska, when 22 total rail cars derailed at 5:45 a.m. Friday.

The train had four locomotives — two in the front and two at the back.

Look to the Tribune for more information as it is released.