Two passenger trains crashed in southern Germany on Tuesday, killing at least 10 people and wounding 80 — 17 of them critically. According to Bavarian police, one person is still missing. The accident in Bavaria happened shortly before 7:00 a.m. local time.

Rescue and salvage crews have been working at the site of the crash near the town of Bad Aibling, roughly 40 miles southeast of Munich. Authorities are trying to figure out what caused the deadly collision. The trains' drivers and conductors are believed to be among the dead, according to local broadcaster Bayerischer Rundfunk.

NPR's Soraya Sarhaddi Nelson reports:

"The head-on crash occurred during the morning rush hour on a remote stretch of track in Bavaria. Rescue workers struggled to get to trapped passengers in the gnarled wreckage on the mountainside.

"Investigators are unclear how the crash could have happened given safety measures that are supposed to prevent trains moving in opposite directions from traveling on the same track."

The trains that collided bear the numbers 79505 and 79506, the company says. Some of the cars derailed during the crash, which happened on a curved portion of track in a wooded area alongside the Mangfall River — conditions that have led to theories that the two drivers couldn't see one another.

When they crashed, the trains had been traveling at speeds up to 100 km per hour — or around 62 mph, reports Deutsche Welle, citing Germany's minister of Transport and Digital Infrastructure, Alexander Dobrindt.

Dobrindt also says that two "black box" recorders have been recovered from the trains.

"The accident was a huge shock to us," says Bernd Rosenbusch, managing director of Bavarian Oberland Bahn GmbH, the parent company to regional train service Meridian.

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