The incident occurred just before 7am (2pm UK time) at a railway crossing in an industrial section of Atlacomulco, a town roughly 80 miles (130km) northwest of Mexico City.
The state civil defence agency of Mexico stated on X that responders were still working at the accident scene, and the state prosecutor’s office had initiated an investigation.
The attorney general’s office reported that seven women and three men lost their lives, and some of the injured are in critical condition.
Images from the scene depict the bus’s roof being torn off, revealing the bus to be a Herriada de Plata (Silver Horseshoe) property.
Video footage from social platforms, appearing to be CCTV of the crossing, shows the bus in heavy traffic moving slowly across the train tracks.
The train then appears abruptly, striking the bus at its midpoint, effectively splitting it into two. The train’s force carries the bus sections down the tracks.
The front half of the bus stops beside the crossing, while the rear half comes to rest further down on the opposite side.
Immediate details on how the accident could have occurred were not provided by authorities. There were no apparent crossing gates or stop lights, according to witnesses.
Miguel Sanchez, 33, who works at a nearby service station, mentioned hearing the train blow its horn before the crossing.
“We heard a crash. We thought it was just a car. We never thought it would be a bus with so many people on board,” Mr Sanchez informed the AP news agency.
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The Canadian Pacific Kansas City of Mexico, the train line involved, confirmed the accident and extended its condolences to the victims’ families. The Calgary-based company stated its personnel were at the scene, assisting the authorities.
It also urged drivers to respect road signs and stop orders at railroad crossings.
The bus company, Herriada de Plata, did not immediately respond to a request for comment.
The Mexican Rail Transportation Regulating Agency’s most recent report, released in September, highlighted 800 accidents at level crossings in the previous year, compared to 602 in 2020.
Last month, a train collided with several vehicles in Guanajuato state, resulting in six fatalities.
In 2019, a freight train struck a passenger bus crossing the tracks in the central state of Queretaro, killing nine people.