application or web interface for freehand plotting tracks on OSM as saving as gpx?

... or even more possibilities at Track_drawing_websites or List_of_OSM_based_Services

If the tracks are part of a recognised trail then try http://hiking.waymarkedtrails.org/en/ and download the GPX file for your route. You can download a GPX for a route of your own creation from OS maps using http://maps.the-hug.net/. Viking can be used to create a track on an OSM basemap also.

If you are a OSM contributor and are already using our advanced editor JOSM, then it is quite handy to also use it to make tracks. This way the known interface can be used, by chance you can spot problems in the OSM data or even plan your route based on bing to collect some new data (surveying) while being on the ride.

1. Add a "Mapnik", "CycleMap", bing, … background layer,
2. add a new (empty) data layer,
3. draw your track in it,
4. export it as gpx.

Of course, be sure to not accidentally upload your track to OSM.

Try this.

Both GPSies.com and wikilic.com allow you to draw your routes on a variety of backgrounds, among them openstreetmap and opencyclemap. The routes can be shared with others. A nice feature of GPSies is that it can "follow" the existing streets, so instead of a straight line between two clicks, your route follows all bends in the road.