Nigels wrote
One of these days I'll have to take a trip to the USA and visit some of your heritage railways - I'm assuming you have them like we do?
Oh yeah, there are a number of historical railroad groups in the US. Federal regulations and/or Class 1 railroad company rules have made things a bit more difficult in the past decade or so. The major issues include the federal requirement for all operating steam locomotives to have welded boilers and the reluctance or refusal of Class 1 railroads to allow engines and rolling stock with plain bearings and older braking systems to run on their main lines.
Still, there are plenty of organizations running steam and early diesel locomotives in the US. The neighboring Cumbres and Toltec and Durango and Silverton both preserve the last surviving section of narrow gauge line of the old Denver and Rio Grande Western. Dollywood in Pigeon Forge, TN also has a long running narrow gauge tourist railway and there are numerous others throughout the country.