We took the high speed train back to Seoul from Daegu. The train goes up to 300 km/h in sections, and was a very convenient way of crossing the country.  It cost us about $40 US per ticket. We got seats in advance, and the train left exactly on time and there was lots of space for our luggage.

KTX High speed train pulling in to Daegu Station

Proof that the train went 300 km/h !