A man killed in a train collision early Tuesday may have intentionally driven his van in front of the speeding University of Colorado A-Line train en route to Denver International Airport, police said.

Fifty-six people were aboard the train at the time. Four were injured in the crash, including one person who was taken to the hospital.

The collision happened at 3:49 a.m. at Chambers and Smith roads.

“When he sees the train he slowly rolled out in front of the train,” said Chris Amsler, spokesman for the Aurora Police Department. “We are investigating whether the collision was an intentional act.”

An off-duty police officer posted at the crossing because of recent timing issues related to the A-line’s at-grade crossings went from desperately attempting to wave off the driver to running for his life as shards of metal from the demolished vehicle flew toward him, Amsler said.

“The officer is out there yelling and waving his arms, trying to get him to stop. And then a ton of debris was flying at our officer,” Amsler said. “He had to run to get out of the way.”

The A-Line train was heading east on the track when the red lights flashed and an alarm sounded, signaling the imminent arrival of a train headed toward Denver International Airport, Amsler said.

The van driver drove past the area where the gates came down and stopped the car. As the train got closer, he began slowly driving toward the tracks.

The train T-boned the van and pushed it about a quarter-mile down the track. It wasn’t immediately known how fast the train was traveling at the time, but the train can reach speeds in excess of 70 miles per hour along some stretches.

The van driver, whose identity has not been released, was pronounced dead at the scene. Adams County Coroner’s office workers responded to the scene and took the body away.

The crinkled front windshield of the van was wrapped around the crossing bar pole. Alarms at the crossing continued sounding at least five hours after the crash.

Large chunks of plastic and metal were strewn along the tracks for hundreds of yards. The van was compressed to about 4-feet wide. It was still attached to the front end of the train as crime analysts snapped pictures and federal inspectors worked at the scene.

Debris from a collision between RTD's A- train and a van strewn all over crossing after fatal crash. pic.twitter.com/KZhbkP86WQ — Kirk Mitchell (@kirkmitchell) February 14, 2017

In addition to the off-duty cop, a flagger from Rocky Mountain Flagging was working the intersection where the crash occurred. They were hired because of problems with the software controlling the safety gates the A-Line’s at-grade crossings from Denver Union Station to DIA.

Aurora police traffic officers will determine whether there is an issue with timing of the emergency crossing bars, Amsler said. The question is whether the bars should close sooner before the arrival of the train.

“That’s one of the things we’re looking into,” he said. “This is the first collision we’ve had.”

RTD spokesman Scott Reed said RTD and Federal Railroad Authority will assist with the investigation.

Toxicology tests will be done to see whether the driver was intoxicated, Amsler said.

The back of the van curled around the front of the train. pic.twitter.com/irCmwyx1qT — Jayson Luber (@Denver7Traffic) February 14, 2017

RTD has reported that the A-Line trains will continue to run from Union Station to Peoria Station and a bus bridge will run between Peoria Station and DIA.

A line operating between Union Station & Peoria Station, bus shuttles between Peoria Station & DIA. Detour likely to last into PM commute. — RTD (@RideRTD) February 14, 2017

Since its April debut, the University of Colorado A-Line has been beset by problems with the timing of its crossing gates, which has necessitated that RTD station flaggers to manually manage the at-grade crossings until the problem is resolved. That has led to a delay in the opening of the G-Line, which uses the same crossing technology.

The Federal Railroad Administration recently granted a waiver allowing the A-Line to continue operating while it attempts to remedy timing issues, Reed said. The waiver expires April 30.

But Reed said the crossing gate timing issues raised by the FRA had to do with the gates going down too early and staying down too long to meet their standards. Motorists were irritated by long waits. He said a software update was done to meet federal requirements.