Elgin police and fire crews responded about 6:30 a.m. to a crash involving a Union Pacific train and a vehicle at the railroad crossing at State Street north of Locust Street, police said.
An adult passenger in the vehicle died on the scene and two other adults were taken to a local hospital, police said.
The person killed has not yet been identified.
The conditions of the injured adults were not immediately released.
Their employer, Cornerstone Partners, said in their statement they are completely focused on supporting the families and employees impacted by this tragedy.
According to a spokesperson for Union Pacific Railroad, the train crew was not hurt.
"I heard like a big boom. I didn't really see much of it. Shortly after that I heard sirens and ambulances," neighbor Faily Williams said.
Chopper 7 was over the scene, showing a silver truck and what appeared to be a trailer of a landscaping company based in Elgin with damage near the tracks.
A stopped freight train was also near the scene.
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A spokesperson for the landscaping company, Cornerstone Partners, issued a statement saying in part, "We are profoundly saddened and heartbroken by the tragedy that occurred today involving our crew."
The crash shut down roads in the area.
A tow truck removed the smashed up pickup truck more than six hours after the crash just west of downtown Elgin.
The National Transportation Safety Board was also on the scene.
Elgin police said there will be temporary stop signs at the railroad crossing until the end of the investigation, which includes Union Pacific completing appropriate inspections.
Union Pacific will also be implementing precautionary safety measures that will include a stop and protect protocol, which involves a train conductor who will visually verify that all traffic is stopped before the train proceeds, police said.
This protocol will be in effect seven days a week.
Train traffic is scheduled from 5 to 7 a.m. and from 9 to 10 p.m., police said.
Neighbors say they have had concerns about this railroad crossing for some time.
"Since I've been here, this is like the third time an accident has happened here. It's really not a safe environment," neighbor Nokia Williams said.
There are crossing gates in place at the intersection.
Investigators are working to determine whether they were lowered when the crash happened.
"It's just dangerous. People walk this way with their kids and stuff," Williams said.
Anyone with information on the crash is asked to call 847-289-2660.