@John Knapp- John I loved your tale of you father's Marx M10000. I am 79 but my toy train legacy was Lionel (started in 1947) so I can't match your history with the M10000. I am very glad to hear yours is still running and providing you pleasure. Marx (and I am now a Marx fan and collector) has a great reputation of building solid, reliable, toys that almost always run regardless of age. I got this M10000 at a train show perhaps 25 + years ago so I can't guarantee that the bulb is original, it is original as far as I am concerned as I have never replaced it. Oh yes...it still runs!!
Best Wishes
Don