national express is for coach, normally slower, and cheapter, if you are not in a hurry. National Rail.com is for trains, and normally it will give you an overview of the train services and prices, and will divert you to different company for purchase, such as Virgin or Crosscountry.
Young person card can be used to get discount for trains, therefore it will be useful for Nationalrail. You can get student discount card for National Express as well, but they are different.
Young person card can be used to get discount for trains, therefore it will be useful for Nationalrail. You can get student discount card for National Express as well, but they are different.
Hope it helps.