We are now offering a download of pre rendered tiles up to zoom level 17 on https://tile.osm.ch/tiles.html. The tiles are split up into the cantons as the whole of Switzerland is quite a large amount of Data.
You can download them to either host them yourself, or use them in an offline application.
The default style on osm.ch now includes contour lines and is updated to the latest version of the openstreetmap-carto style sheet.
(c) OpenStreetMap contributors
Elevation data created from a mash-up of SRTM and ASTER GDEM data. ASTER GDEM is a product of METI and NASA. Post processing was kindly provided by Yves Cainaud from opensnowmap.org.