Given a travel related situation, and given a specific question about the situation, summarize the question into a title
Q: Specifically, I am taking the train from Taipei to Keelung, getting off at Badu and going to Pingxi, and then returning at night.

Do trains tend to sell out in Taiwan, or should I be OK purchasing my ticket immediately before departure?

A:
In Taiwan, must you reserve train tickets in advance, or can you buy tickets a few minutes before trains are supposed to depart?