Each passenger is generally allowed to bring luggage without specific checks or counts, as long as they hold a valid ticket for the journey. The total weight of your luggage should not exceed 40kg. As for size, no piece of luggage should be longer than 150cm, and the total combined length, width, and height should not exceed 220cm.
If your luggage exceeds these limits, Taiwan Railways may require you to purchase an additional seat or incur other expenses. There are no designated check-in counters like at airports, so any decision regarding oversized luggage will be made at the station.