Volunteer music librarian here, got the following from a radio listener. Does this ring a bell with anyone?
‘Somewhere long ago I heard this lyric in a song. I think the line was,"It's always made me wonder, that steel made of thunder..." this was back in 1975 or so. I may have heard it on WFMT show the Midnight Special. Anyway, my friend asked me where I heard that phrase and I thought it may have been a song by U. Utah Phillips. I looked at his website and after some searching could not find that phrase in a song. Perhaps it was another singer/songwriter. Do you or any of your listeners know the source of "steel made of thunder.." in a train referenced song?‘