Hello Ian and a very warm welcome to the forum. I think that what you saw was the returning "Cumbrian Mountain Express" which ran Kings Cross-York-Carlisle-York-kings Cross that day and was scheduled to call at York at around 7pm. This was a one off excursion but don't be put off by that, there are frequent excursions in all directions all run by firms specialising in days out by train. If I can point you in the direction of
http://uksteam.info/tours/index.htm this will get you a list of tours hauled by Steam Locos and the promoters thereof. Perhaps another forum member would be willing to supply you with details of those promoters using diesel or electric traction. Whichever you choose, I hope you enjoy it.
Regards, 62440.