Oct. 23 (UPI) -- One passenger is dead and 15 others were injured when two trains in mid Wales collided, officials said Tuesday.

The crash between the two passenger trains occurred at 7:26 p.m. local time on Monday, in Talerddig, Powys, Britain's Rail Accident Investigation Branch said in a statement.

The deceased has been identified by British Transport Police in a statement as a man in his 60s. Authorities said the circumstances leading up to his death are under investigation.

Of the 15 people hospitalized, four suffered serious injuries, the RAIB reported.

According to authorities, the railway at Talerddig is a single track, and a passing loop is used to allow trains to pass one another safely. The crash occurred about a half mile west of the passing loop.

RAIB said an initial inspection of the track near the collision point found evidence suggesting one of the trains "may have entered into wheel slide when braking."

Officials said the collision occurred at a speed of 15 mph.

"We are deeply saddened by the train crash that occurred in Wales last night," Martin Frobisher, director of safety and engineering for Network Rail, which oversees Britain's railway infrastructure, said in a statement.

"Our thoughts are with everyone affected by this tragic incident, including passengers, train crew members and their families."