The Nippori-Toneri Liner, which runs in Tokyo’s Arakawa Ward and Adachi Ward, had hassle briefly suspending operation for 4 days in a row in April, and one of many causes was that the pantograph bolt had come off. Interviews with individuals concerned revealed that the rationale for this was that they forgot to tighten it. The Metropolitan Transportation Bureau has determined to place collectively measures to forestall recurrence.
Source
Nippori/Toneri Liner Part of the difficulty is forgetting to tighten the bolts | NHK
