I think I understand this, but am just checking, and I know I can ask when I buy my ticket:
I have printed out the schedule for several departures times from Paddington to Abergavenny (not knowing when I will get to Paddington and so not knowing which train to take and planning to buy a ticket at the station) and under the words "London Paddington" on my printed-out schedule it says "Great Western Railway towards Swansea." I assume that means my train, though I am getting off in Newport to change, will say "Swansea" on it somewhere, right? And when I catch the next train -- "Newport (South Wales)...Transport for Wales towards Holyhead" THAT train will say "Hollyhead" on it somewhere, even though I am getting off in Abergavenny, right? And I will need to locate that track in Newport by the word "Hollyhead," right?
When I get off the train to change in Newport, will there be a sign very close by with the track listed for my next train? I may not have much time.
How can I be sure I am sitting in a car that will actually get me to my destination in case I don't have a reserved seat?