The lingering offensive odor on these streetcars is undeniable. The seats are darker than the other streetcars because they're so soiled by the unclean bodies of the homeless Queen Street inhabitants. A lot of smelly people evade fare by slithering onto this streetcar. There is a lot of back door entry going on, especially at the Church St stop.
One time, all passengers were evacuated because of "unsanitary conditions" which was a used tampon on the ground. Blech! So if you can, AVOID this street car, but if you can't, just don't sit down. You can't tell whether the seat is wet or not because they're all sooooo soiled. And also, if you grab some food before getting on the 501, seal it, put it away. Don't think for a second that it's okay to ingest anything on this streetcar. You'll be inhaling the skin flakes of people who live with inch thick layers of body dirt. The only good thing about the 501 is that the sticky floors usually indicate which of the seats are sticky.