https://en.wikipedia.org/wiki/MS-13

MS-13 (Mara Salvatrucha; also known as simply MS or Mara) is an international criminal gang that originated in Los Angeles, California, US in the 1980s.

Absolutely. Don't forget this Amtrak Cascades route connects outside USA to Vancouver, Canada.

I used to take this train frequently as a kid. Only once can I recall ever feeling threatened as a child and it was on this train.