Front of brand-new DBAG S-Bahn EMU 423 555-2 as a Düsseldorf-bound S11 train on the northbound track of Köln-Nippes station, June 2000.

Class 423 EMUs consist of four articulated cars, running on five bogies. Unlike class 420, it is possible to walk through the entire trainset. 423s can be coupled with other units of the same class with the automatic coupler seen here.

Photo and scan: Klaus von der Heyde