In the early 1990s, the development of a successor series for the S-Bahn trainsets of the → class 420 began. They were designed primarily for the Munich S-Bahn services, but are also in use on the S-Bahn networks in Stuttgart, Cologne, and around Frankfurt (Rhein-Main). The first trains were delivered in 1998. By 2007, a total of 462 trainsets had been built. After that, furter modified units were manufactured for the S-Bahn Rhein-Ruhr as class 422 until 2010. The most striking change is the new front design with an enlarged crumple zone. The class 430, which has been built for the S-Bahn Stuttgart and Rhein-Main since 2012, is also based on the "423".