When to map what?
In short:
- Walking trail: For non-drivable, with possible destinations
- Pedestrian Boardwalk: For non-drivable, without destinations. Also used for Public Transport by Bus
- Stairway: Can be used to indicate stairs without routing functionality in WME
- Railroad: railway lines, metro tracks and tramways, see above
- Runway/Taxiway - designated for airplane taxiing lanes on airports, see above