The DBAG Class 611 is a two car, tilting, diesel multiple unit operated by Deutsche Bahn for fast regional rail services on unelectrified lines.

Class 611, successor to the DB Class 610, was developed using tilting systems from German military technology in favour of the Hydraulic Fiat systems used by its predecessor[citation needed] Because of environmental concerns over the potential hazards of leaking hydraulic fluid an electrically actuated option based on equipment used to keep the guns of tanks level while traversing uneven terrain was used.

[1] The Class 611 suffered teething troubles following its entry into service just two years after the contract was awarded and was largely considered a failure.

The Federal Railway Authority limited the Class 611 to 120 km/h and required the tilting technology to be disabled, this was only reversed in May 1999 when they were satisfied the issues had been resolved.

The tilting was disabled again in August 2004 when cracks were found in the 611's successors wheel sets, the DBAG Class 612, during ultrasound examinations of the axles.