Proceeding slowly. In railways, refers to trains that stop frequently and run at a slower speed (local trains).
この区間は工事のため緩行運転になっている。
This section is operating at reduced speed because of construction.
急行が通過する駅には、緩行列車だけが停まることが多い。
At stations where express trains pass through, usually only local (slow) trains stop.
朝のラッシュで緩行と急行が混在すると、ダイヤが乱れやすい。
When local and express trains mix during the morning rush, the timetable is easily disrupted.