BEIJING -?Trains on Beijing subway Line 1 were out of operation due to signal problems, according to the Beijing Subway official microblog early Thursday morning.

The company said all the stations on Line 1 were "exit only" as of 8:30 a.m., one hour after it announced the delay. Passengers onboard were advised to take other means of transportation.

The mechanical breakdown coincided with the work day rush hour and an overnight rain that the city's weather bureau forecast would aggravate to a downpour sometime in the day.

Mobile Internet users posted photos and comments online, complaining the lack of pre-arranged planning on the part of the subway operator that should be responsible for their being late for work.

Photos of overcrowded platforms and train compartments went viral online, incurring comments of frustration and criticism.

The suspension has also led to minor chaos on other lines connecting to Line 1, according to commuters.