The train crosses the wild heart of Sicily — mountains, gorges, abandoned villages. 2 hours, and the Valley of the Temples makes it one of the island's most worthwhile journeys.
Palermo Centrale → Agrigento Centrale. Direct, beautiful interior route. Then local bus to the temples.
Frequent, sometimes faster. From Piazzetta Cairoli.
Train for scenery, bus for speed. Both 2 hours, both work well.