I've never been on one on the proper railway.
As much as I tell myself I should, since I certainly do have the interest (I know a Castle from a Black Five, and I'd have sold my grandmother to ride behind Tornado at the intended line speed for an A1), but something always stops me.
The cost? Easy to say, but I genuinely couldn't tell you what the cheapest steam railtour even is. And I've certainly spent silly money on my hobbies in the past.
The perception it's for proper enthusiasts? Rivet counters bore me. But I bore muggles.
The fact I would have to go alone? Because somehow it would be worse if I guilt tripped a friend or loved one into doing something they're probably not interested in, just to humour me. People who quite happily come to a heritage railway.
The fact it's not for enthusiasts at all maybe? Peering in the windows of a steam tour this Summer that happened to have stopped in my station, didn't exactly reveal an array of anoraks and flasks. Lots of extremely well dressed pensioners enjoying very fancy food. Probably had no clue what their locomotive even was (44871). Having a bloody good time though.
I'm perhaps a curious market, falling between two stools, served by nobody perhaps. I want to take a steam tour both because I like (and know a sad amount about) steam, but I also like the idea of being wined and dined and seeing the destination as much as enjoying the traction. I've got the time and the money, but I'm not a retiree.