A semi-truck and a Regional Transportation District commuter A line train crashed into each other on Monday morning, resulting in minor injuries to the train operator and multiple passengers.

The crash occurred around 9:21 a.m. at the Sable Boulevard grade crossing near Smith Road, according to RTD officials.

It is unclear what led to the semi-truck and A line commuter train to collide.

An RTD spokesperson said 57 people were on board during the crash.

Aurora Police Department officials said three people suffered minor injuries. The extent of those injuries remain unknown. The truck driver was not injured.

An Aurora police spokesperson warned of long delays throughout Monday.

“There is extensive damage to the railway safety equipment, meaning there is going to be a significant traffic closure in the area,” the spokesperson said.

Eastbound and westbound lanes of Smith Road are closed, according to police.

Police said drivers should detour along Chambers and Peoria as alternate routes.

A bus shuttle service was in place between Central Park station and 40th and Airport station for passengers, before the service closed at 1:52 p.m., according to RTD officials.

Service on the A line reopened between the two stations just before 2 p.m.