In 2010, after the Swiss Federal Railways (SBB CFF FFS) introduced the Twindexx as a double-decker tilting train, concerns regarding motion sickness reemerged, reflecting past experiences with the RABDe 500 "ICN" tilting trains. Following the commissioning of these units in 2001, the CFF conducted a survey among users to gather their opinions. Many respondents raised concerns about motion sickness, which was attributed to the train's active tilting system.

During the design of the Twindexx, Bombardier prioritized passenger comfort. The Twindexx is the first train equipped with new bogies from Bombardier, known as the FLEXX Tronic WAKO.

To assess its functionality and effects, two WAKO units were installed under unit 50 85 16-94 055-0 during a testing period in early 2011. The tests yielded positive results, leading to discussions about retrofitting part of the existing CFF fleet, including the IC 2000 passenger coaches and the Unified cars IV / Einheitswagen - EW IV / Voitures unifiées - VU IV, with WAKO technology. This project was ultimately not pursued by the CFF.