The governor of the state of Kentucky in the United States has warned that more than 50 people are thought to have been killed in the storm overnight.
Andy Beshear said the figure could be as high as 100 at what he called the worst hurricanes in the history of the state.
Scores of people are feared to have died in the candle factory in the town of Mayfield.
At least five people have been killed as hurricanes have wreaked havoc in other states, including one at an Amazon warehouse in Illinois.
Mr. Beshear declared a state of emergency in Kentucky.
More than 100 people were inside the Mayfield factory when the typhoon hit, he said.
“We believe we will lose at least a lot of those people,” the governor said.
Police said the typhoon caused “significant damage” to the western parts of the region. The train was wrecked during Hurricane Hopkins County, Sheriff Matt Sanderson told WKYT-TV.
He also described the two children who were reported missing during the cyclone but were found in an exhaust bath.
“There were two children in the Barnsley area who were missing and were found in the bathtub which was not where the house was originally located,” he said.
The Amazon warehouse in Edwardsville in southern Illinois was damaged during a hurricane Friday night, authorities said.
It is not yet clear how many people were injured in the collapse, but local paramedics have called it a “mass casualty” incident on Facebook.
Illinois police chief Mike Fillback said at least one person had died.
Sarah Bierman said her partner had not yet been found.
“I spoke to him at 8 pm, just before I texted him, he was returning to the warehouse to drop off his van. And I have never heard of him,” he told Reuters.
“I decided to come down here to see what was going on. I didn’t know this building looked so bad. And I just … I’m worried about illness. I want to know if you’re okay,” he added.
“My prayers are with the people of Edwardsville tonight, and I have been in contact with the mayor to provide any needed government resources,” Illinois Governor JB Pritzker tweeted.
Amazon was assessing the situation and the damage, a spokesman said in a statement.
Tennessee Emergency Management Agency spokesman Dean Flener said two people had died in Lake County and one in Obion County, northwest of the region. No further details were provided.
In Arkansas, one person was killed, five were seriously injured and 20 people were trapped inside a nursing home after the crash, Craighead County Judge Marvin Day said.
The detainees were rescued but the building was “severely damaged”, he added.