40 Class 424 electric multiple units were acquired especially for the Hanover S-Bahn. These differ from the vehicles of class 423, as they have a lower floor height of 80 cm, fewer doors and include toilets. Although delivery began as early as 1998, the class 424 trains were not yet ready for the opening of the S-Bahn network at the start the Expo 2000 due to technical problems. Deutsche Bahn therefore had to temporarily borrow class 423 rolling stock from the Munich S-Bahn.