In July 2010, SBB Cargo awarded Stadler Winterthur a SFr88m contract to supply 30 electro-diesel locomotives for shunting and light freight duties. The two-axle design is derived from the electric Ee 922 locomotives. Stadler Rail has nicknamed both shunting locomotive products 'Butler'.
On 14.10.2011, SBB Cargo and Stadler Winterthur AG presented the new hybrid locomotive, type Eem 923. In 2012, first commercial services with these new machines started.
Unit no.005 was present at InnoTrans 2012. The pictures the new machine amongst many other new vehicles with Swiss roots.