The DBAG Class 474/874 is a three-car electric multiple unit train for the Hamburg S-Bahn.

Some units have a pantograph (474.3) to service the 2007 opened line to Stade on an overhead catenary track.

Following severe vibrations, there were deficiencies in the ventilation system, the door opening mechanism and the engine, which led to an acceptance stop.

The vehicles are additionally equipped for overhead line operation with a current of 15 kV at 16.7 Hz.

The class 474.3 multiple units have been in scheduled service since December 2007 as the S3 from Pinneberg via the “City Tunnel“ and the Niederelbebahn to the S-Bahn terminus at Stade.

However, due to technical difficulties (including excessive weight of the air-conditioning system), the conversion prototype could not be approved.

For technical reasons and in order to avoid a new approval procedure, the installation of an air conditioning system was dispensed within the further planning.

On Friday, January 9, 2015, the 4012 conversion prototype, now without the air conditioning system, was presented as the first modernized series train, which went into service soon after.

[4] In May 2019, half of the planned conversions had been carried out, and the modernization of the entire fleet was scheduled for the end of 2021.

Content in this edit is translated from the existing German Wikipedia article at de:DB-Baureihe 474; see its history for attribution.