Hi Bookman,
There are many photos of the original "Red Dragon" in railway books especially ones by George Heiron but they are few and far between on the Internet.
There is a photo of a Castle being prepared to work the "Red Dragon" here:-
http://www.davidheyscollection.com/userimages/j-payne-5077-red-dragon.jpg and this site has greetings cards and prints which feature a Britannia hauling the "Red Dragon" at Newport:-
http://asp.kandles.co.uk/acatalog/Greeting_Cards.html
I should have mentioned it earlier but for a while there were actually two "Red Dragon" trains operating. The main one that we are talking about and a local shuttle that ran in North Wales between Rhyl and Llandudno