> Is the subway system in Boston relatively safe?

On it's most dangerous day, it's still a heck of a lot safer than driving.

Sure, there's an oddball on the T from time to time, maybe a drug addict dozing off. They're mostly harmless. But I've lived here about a decade and never had any issues. At worst, a bus I was on broke down and I had to catch the next one.

Normal city rules apply - so a little vigilance is recommend.

> What about getting off at a station at night?

Pretty much anywhere a tourist will be in Greater Boston area is safe at night. I see the closest station you'll be is Lechmere, you have nothing to worry about.

The Green Lines are a little slow (they're light rail trolleys, unlike the Blue, Orange and Red which are heavy rail subways) - but it'll get to where you need to go.

Have fun, enjoy!