CHICAGO >> A Chicago commuter train collided with rail equipment Thursday morning, injuring nearly 40 people, some of them critically, fire officials said.

The Chicago Transit Authority train crashed into snow-removal equipment just before 10:35 a.m. on the city’s North Side near the Howard CTA station, the Chicago Fire Department said.

The Yellow Line train carrying 31 commuters and seven CTA workers was heading south from Skokie when it collided with the slower-moving rail equipment, said Robert Jurewicz, the Chicago Fire Department’s second district chief.

Thirty-eight people, including four children, were injured. Twenty-three were taken to area hospitals and three of the injured were in critical condition, although no one suffered life-threatening injuries, said Keith Gray, assistant deputy chief paramedic. The train’s operator was among the most seriously hurt, the Chicago Sun-Times reported. The children suffered bumps and bruises, the newspaper reported.

Gray said the 15 others who were on the train declined medical treatment at the scene.

The National Transportation Safety Board tweeted that it was sending a team to investigate the incident.

Humdia Ahmad told the Chicago Tribune that she was riding in the train’s second car on her way to DePaul University when she heard a thud and was flung forward. She said she wasn’t hurt, but as emergency responders helped her off the train she heard the train operator screaming in pain and saw blood on the floor and rails.

“When we actually got out I saw the front of the train, and it was completely busted open — the glass, everything,” she said. “Thank God I’m OK, but I was very worried for everyone in the first car who had to experience that.”

Shayla Smith, who was headed to work in Wilmette, had just boarded a Purple Line train at Howard when she heard the collision. She said passengers on her train began screaming, and she saw an elderly woman nearly fall out of her seat.

“I just heard like a horrible boom sound,” she told the Sun-Times. “It was like a weird boom sound. It felt like we’re gonna tip over and I was wondering what’s going on? My body shivered.”

Television video showed one end of the train crushed and pushed in.

As passengers were led off the train, some were brought into a triage center lined with stretchers to be assessed, with at least one person seen bleeding heavily from the head.

At least 15 ambulances were dispatched.

CTA officials said the cause of the crash remains under investigation. Train service on CTA’s Red, Purple and Yellow lines had been temporarily suspended because of the crash, the commuter service said on its website.