[meteorite-list] Hypothetical launch question

[bill kies]

I had an interesting call from a gentleman in Lombard Illinois. He has an 8 pound rock that bounced off his roof. After careful examination, I explained that it was probably not a meteorite but that it wasn't my place to discount the possibility entirely. I suggested he have a piece sliced and polished since he was so determined to know for sure. 

The question of how this rock got there is still kind of interesting. It did quite a bit of damage to his roof and ceiling but it didn't penetrate the old roof. I suggested, to muted ears, that a beast that size would have easily crashed through had it been falling at terminal velocity. 

There are three railroad lines near his home. Can anyone imagine how an ore car might launch an eight pound rock 5 blocks?

Bill