Signal problems, heat may have played role in collision of 2 French trains

An employee of the railways works as the scene after two trains collided in Deguin, near Pau, southwestern France, Thursday, July 17, 2014. A regional TER train and a national TGV train heading for Paris collided head on after traveling on the same track in opposite directions in the town of Deguin, 18 kilometers (11 miles) northwest of Pau and left 25 people injured. (AP Photo/Bob Edme) (The Associated Press)

Vice prosecutor Sebastien Ellul, left, and French police officers at the scene after two trains collided in Deguin, near Pau, southwestern France, Thursday, July 17, 2014. A regional TER train and a national TGV train heading for Paris collided head on after traveling on the same track in opposite directions in the town of Deguin, 18 kilometers (11 miles) northwest of Pau and left 25 people injured. (AP Photo/Bob Edme) (The Associated Press)

PARIS – France's transport chief says faulty maintenance on a signal and hot weather may have played a role in the collision of two trains in southwest France, which left 25 injured.

France, whose extensive train network is widely used by tourists in summer, is upgrading railways nationwide as part of larger reforms of the industry.

A regional train hit a slower-moving national TGV train bound for Paris from behind Thursday evening in the town of Deguin.

Frederic Cuvillier said on Europe-1 radio Friday that "maintenance on the signals appears to have been disrupted and faulty." He noted that heat can also cause signal problems. Cuvillier would not say whether the accident was due to human error or technical problems.

Nine of the injuries were serious, authorities said.