Subway Trains dream of a subway train represents a direction in life or long term goal that has regular breaks along the way. You may be working towards something or waiting for something that you notice regularly stops or changes. Awareness of a goal taking a lot longer than you want it to. A fast paced transition that require numerous pauses along the way.
Negatively, a subway train in a dream may reflect impatience at having to keep stopping during a very fast pace experience. An unstoppable recurring experience you are having that other people may not be aware of you having. Trying to do something quickly without other people seeing it. Dislike of having to feel like you are wasting any time at all. Wishing you could complete a goal without any pausing.
Alternatively, a subway train may reflect short periods of opportunity that arise as you work towards longer term goals.
A man dreamed of being on a subway train. In waking life he was trying to quickly clean up a regulatory issue with his business that required frequent pauses to be reevaluated by a professional to determine his new regulatory status based on changes he was making. He was annoyed at having to frequently stop the improvements to his business to get the reevaluation because it preventing him from cleaning up the regulatory problems in one quick action.