"Usually" being the operative word. There are four weekday East Coast HST diagrams that operate services entirely under the wires, all day. There are also a couple more that only spend a short amount of time away from the wires in a day, such as the set that starts at Hull in the morning and finishes at Lincoln in the evening. East Coasts' HSTs serve a lot more destinations than just the Aberdeen and Inverness services.HSTs are the Aberdeen/Inverness services. 225s are uselly Edinburgh services.