A Deutsche Bahn ICE train failed to keep its door closed while traveling at about 200 km/h in a tunnel near Karlstadt, prompting a police-led investigation and a drone search for passengers.

ICE 528, en route to Frankfurt, stopped in a tunnel near Nantenbach after the emergency brake deployed, with 238 passengers aboard.

An ICE train near the Hessian-Bavarian border halted in a tunnel after an emergency brake was triggered by an open exterior door.

The incident occurred on September 1, with official timing and location confirmed, according to a dpa source.

Investigators continue, checking for the responsible person and reviewing surveillance; the line was cleared around 2:30 a.m., and Deutsche Bahn has not commented further yet.

The event is treated as a serious safety matter, with authorities seeking to verify door integrity and understand how the door opened at speed.

Timeline notes a high-speed event; a 32-second video clip accompanies the report, with a 13:30 timestamp for the stand-alone footage.

The incident occurred on Tuesday evening, September 1, 2026, and the cause of the door opening remains unknown at the time of reporting.

Deutsche Bahn ruled out a technical defect, and Bundespolizei suspects a manually activated emergency release rather than a mechanical failure.

Door security: normally doors are locked during travel and released only by the driver; an emergency release behind an acrylic glass panel can be pressed only in danger, but the panel was damaged, making the button accessible.

Initial explanation indicates the door opened via the emergency unlock mechanism, activated through the acrylic panel during an emergency.

Authorities have not determined who pressed the emergency release; the act is treated as a potential crime, with passengers being interviewed and statements collected, including around 120 identified from the rear of the train.