They announce the reason for substantially all unscheduled stops. The most common is 信号待ち (waiting on a signal)。It is my impression that, in Japan, the lion’s s

They announce the reason for substantially all unscheduled stops. The most common is 信号待ち (waiting on a signal)。It is my impression that, in Japan, the lion’s share of those are discretionary on the part of the station staff for safety reasons. (This is not true of the US, where ops on railways are rather substantially more... organic.) Source: uncle worked in dispatch room in US; many of my salarymen comrades were train buffs and they tried to convert me.