[BooBoo1000]

45 Colt, on a crowded train, bad idea, perhaps a 9mm with hollow points,but an old slab side would take out the perp and about 2 more people standing behind him. I guess you could round up all of the perps, get them lined up and shoot the entire damn bunch, Might get a Civic Improvement Award.

[JrsyJack]

45 Colt, on a crowded train, bad idea, perhaps a 9mm with hollow points

A .45ACP travels a bit slower than a 9mm, besides they make HPs for .45s as well, nasty as they come...

[GladesGuru]

Many ammo brands have rounds which will not penetrate a perp. Just avoid the old FMJ cheap white box stuff From WallyWorld. Better yet, avoid Skippy, the Walmart ammo salesman and patronize your local gunshop.

PS Consider advanced training, and from local instructors to traveling to a Profire or Frontsight course, there are lots of options.