^ there's often bound to be a few places on most systems where an at-grade street crossing or two occur.
hell, even on chicago's heavy rail el system, 4 of the lines (purple, yellow, brown, and pink) have some at-grade street crossing at their extremities.
in fact, i live
right at the spot where the brown line transitions from steel elevated structure to running at grade. my local el stop is one of the unusual at-grade ones right at an at-grade street crossing.
source:
https://www.chicago-l.org/stations/rockwell.html
and i grew up in suburban wilmette a couple blocks away from an at-grade street crossing at the very end of the purple line. i guess i just have a thing for that sort of thing.
i wonder if any of the other heavy rail rapid transit system in the US have any at-grade street crossings?