I’ve brought back the MapRoulette US Railway crossings challenge with a slight difference - the remaining tasks are derived from a topological look at the OSM data.
[Crossing Ways: Highway-Railway, US] http://maproulette.org/map/980
[Crossing Ways: Pedestrian-Railway, US] http://maproulette.org/map/989
[Crossing Type: Highway-Railway, US] http://maproulette.org/map/990
[Crossing Type: Pedestrian-Railway, US] http://maproulette.org/map/991