miss the train
'Perder el tren' is a Spanish phrase that translates as 'miss the train' in English. It can be used literally to describe the scenario of not arriving in time for a scheduled train. However, it is also commonly used idiomatically in Spanish to express the idea of missing an opportunity or being too late to take advantage of a situation. Just as in English we use the phrase 'miss the boat', in Spanish they use 'perder el tren'.
If you don't hurry up, you are going to miss the train.
This statement can be used literally, if somebody is at risk of not catching a train due to some kind of delay. It could also be used metaphorically to imply that an individual may lose an opportunity if they do not act quicker.
Missing the train, that is my biggest worry right now.
In this case, 'missing the train' is the main subject of concern, which might mean the speaker is in a rush to catch an actual train. Alternatively, it could indicate that the person is anxious about missing out on an opportunity.
To avoid missing the train, I always arrive at the station a half hour early.
This individual is demonstrating a proactive strategy to avoid the unpleasant situation of 'missing the train'. They arrive early to assure they won't miss out, whether that involves a real train or an opportunity.