As documented at osm.wiki/WikiProject_Poland/Warszawa#Linie_kolejowe_i_tramwaje (Polish) I have now assigned the tags tactile_paving=yes/no and (if yes), tactile_paving:slab_size=35x35 or 40x40 (cm square) according to the data from the Warsaw tram operator that arrived in my mailbox in December, which I requested in August -- nevertheless kudos to them. The names of nearly 500 tram stops equipped with tactile paving was printed on 16 pages of paper (yes, those rectangular white sheets).

Next thing, now that I know we have all or nearly all stops in the city, is to script creation of tram route relations and keeping them up to date using the schedule data availabel through the operator's web api. Hopefully the script will be reusable for other cities and for bus / train routes too.

My current idea is to store (outside of OSM database) the fragments of routes between each two adjacent stops and combine them to form a full tram / bus line route when updating. Where there's no connection between two stops stored yet, just use shortest path in a graph to find a route, later when a human editor fixes the relation, the new route fragments will be stored on next update.