Swiss Locomotive and Machine Works (German Schweizerische Lokomotiv- und Maschinenfabrik; French Société Suisse pour la Construction de Locomotives et de Machines; or for both SLM) were a railway equipment manufacturer based in Winterthur in Switzerland. Much of the world's mountain railway equipment was constructed by them.
1998 the Cog-Railway division was sold to Stadler Rail, the Engineering division via Adtranz to Bombardier Transportation. The remaining Business was renamed as Sulzer-Winpro AG and as part of a Management Buyout in 2001 renamed in Winpro AG. The Advanced Steam division was sold in 2000 to DLM AG. In October 2001 the Measurement Division was sold to PROSE AG. Winpro AG was sold on 7 September 2005 to Stadler Rail.