Dali Railway station is the main way into the town.

What's great for travelers is that it's really well served on a line that hits all the sweet spots including Kunming, Lijiang and Shangri-La.

note that the train station sits in the "new" part of town to the south of the lake, whereas the main ancient town is on the west side to the north of the station so you'll either have to get a cab or a bus to get there.