Actually if it was really a blasting cap, then I can't imagine what it was doing along the RR tracks in Florida. Out in the mountains somewhere, fine it would make some sense for someone trying to bring down part of a mountain or build a tunnel. So my guess would be that it was either dropped by someone, for some reason we may never know, or perhaps it fell out of a freight car.
There also is something called a railroad torpedo, which is what Hokie is thinking of I believe. I'm not sure however that it's powerful enough to take someone's toe off. Railroad torpedoes were used years ago as a warning device, largely back before we had signals and radios. AFAIK they were typically used when a train stopped in an unusual place, typically because it broke down for one reason or another. But I believe sometimes they also were used on sidings.
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