Reminds me of the very old joke. "Why couldn't the railway engine sit down"? "Because it had a tender behind". Sounds like it would fall completely flat with my grandchildren!
(My bolding) -- @stuu, I don't disagree with the rest of your post; but, re the bolded part: I'm 75, and recall having heard in my childhood, @DerekC 's above joke (or very near equivalent -- in my case it was, paraphrasing, "why is a boy who has recently undergone corporal punishment, like a railway engine?") -- those from whom I heard it, were not particularly railway-besotted.I'm not sure tender would ever have been all that common a term, you would surely have had to be interested in railways in the first place. I know that was more common previously when there were less distractions, but you would have to be ~65+ to have any serious recollections of working steam. The generational shift would have been a long time ago I would have thought