The BLS RABe 515, also known as MUTZ, is a class of bilevel electric multiple units manufactured by Stadler Rail for BLS AG. It is a second-generation derivative of the Stadler KISS. Formations are composed of four or six cars. They were the first bilevel cars used by BLS.

BLS AG is a Swiss railway company created by the 2006 merger of BLS Lötschbergbahn and Regionalverkehr Mittelland AG. 55.8% of it is owned by the canton of Berne, and 21.7% by the Swiss Confederation. It has two main business fields: passenger traffic and infrastructure.