I ride the DC Metro in to work. I typically ride in the last car of the 8-car trains (when they're available), which I prefer because usually no one's on it...but the flipside is you never know if someone who's mentally ill, strung out, or just looking for trouble hops on, and it's just you and them.
And Metro's had some serious incidents over the years, including just a couple months ago when a Metro employee was murdered inside one of the stations (one that I sometimes disembark at, depending on how far I feel like walking), totally random. And a tourist(?) was stabbed to death on the Red Line on July 4th some years ago. Metro crime in general has really picked up lately.
So yeah, I worry or at least think about it, but don't usually dwell on it. My attitude over the years has basically become Que sera, sera.
I do carry pepper spray and have a stealth tactical keychain. I'd rather not be caught slippin' if, heaven forbid, anything ever went really sideways. Hopefully I'd be quick enough to react though - I ain't getting any younger...

