A crowded escalator at the Stockholm City commuter train station suddenly went dark last summer.

No one was seriously injured, but Stockholms Lokaltrafik decided to shut down all escalators of the same model at Stockholm City and Stockholm Odenplan stations pending an investigation.

Now comes the answer: the construction of the escalators' coupling was not robust enough to withstand the wear and tear it was subjected to. This is shown by the inspection company Dekra's report.
All affected escalators are now being repaired by manufacturer Otis and the work is expected to be completed in May. In total, the coupling between the motor and gearbox on 25 escalators will be repaired and an additional brake will be installed on 65 of them.
SL regrets that it will take some time before all escalators are operational again.
”"What has taken the most time is manufacturing the new parts, after which they must be checked, installed, inspected and the escalator tested before it can be put into operation again," says Caroline Ottosson, head of the traffic administration, in a press release.

Source: TT