I installed a new speaker in the subway engine today & yes, it does have an engine sound. There was a lot of flaking (magnet disintegrating), on the old speaker. As George suggested, even though some sounds were playing, but a little garbled, the engine sound was not audible, I guess, due to it being a different frequency.
I'm not very familiar with most of these engines & their electronics, but the guts were really shoe horned in! I hope I got it back together ok. It seems to be running as I remember, so I'll keep my fingers crossed.
Thanks for the suggestions.
Joe