Jose, when you say "subway grate," where does said "business" drip? On the subway tracks, or on the people underground, or where?
All of the above. Or below, as the case may be.
Thankfully, most of the subway grates are also set up as storm drains, so that no water - or other liquids (or solids

) - falls onto the tracks or passengers. It all goes into the sewer system. -But there are a few stations where it sometimes "rains" inside the station even though it's not raining outside the station. -Yeah, I know, gross and TMI.