A passenger at JR Ryogoku Station couldn't get on the first outbound JR Sobu Line train of the day Tuesday after a station employee accidentally locked the keys in an office, East Japan Railway Co. officials said.

The incident occurred a little after 4 a.m., when the employee left the station office to turn on the ticket vending machines. He inadvertently left the keys to the office, as well as to the station's entrances, inside the office, only to find himself locked out when its door closed, the officials said.

The employee eventually retrieved the keys after breaking a window to the office, but in the time it took to open the station's entrances, the passenger was unable to board the 4:35 train out of JR Ochanomizu Station to Chiba Station and had to wait for the next train, they said.