DB Class 628

DB Class 628
Class 628.4 diesel railcar
Quantity	304
Manufacturer	Düwag, Waggon Union, AEG and others
Entered service	1986–1996
Axle arrangement	2'B'+ 2'2'
Track gauge	1,435 mm (4 ft 8 1⁄2 in) standard gauge
Length over buffers	46.15 m (151 ft 4 7⁄8 in) married pair
Minimum curve	125 m (410 ft)
Total weight	77.0 t (75.8 long tons; 84.9 short tons)
Service weight	42.0 t (41.3 long tons; 46.3 short tons) (VT) / 29.0 t (28.5 long tons; 32.0 short tons) (VS)*
Top speed	120 km/h (75 mph)
Installed power	485 kW (650 hp) at 2100 rpm
Tractive effort	Vierfach
Motor make/model	MTU 183 TD 12
Motor type	V12 diesel with turbocharger and charge cooling
Power transmission	fluid converter coupling
Transmission model	Voith T 311r WK
Tank capacity	1,000 L (220 imp gal; 260 US gal) diesel
Brakes	KE-R-A
Train protection	Sifa / PZB
Anti-skid protection	electronics
Train heating	250 L (55 imp gal; 66 US gal) heating oil
Train control	MICAS (microprocessor-supported multiple-unit control)
Seats	146 (72 VT, 74 VS)
Doors	double swinging-sliding doors (inside width 1,280 mm or 50 3⁄8 in)
* with 2/3 supplies

The DB Class 628 is a twin-car, diesel multiple unit operated by the Deutsche Bahn AG for local passenger rail services.

(The following description is primarily related to the Class 628.4, and is largely valid for the other variants as well)

Each coach rests on two twin-axle bogies. Only the bogie at the close-coupled end of the coach is driven. Power transmission from the motor is achieved using a Voith hydrodynamic transmission system with a converter (Wandler) and a T 311r coupling. Up to Class 628, a T 320 double-converter transmission was used. Motor and transmission are suspended elastically under the lightweight coach body. The operating brake is an automatic compressed air KE disc brake with automatic load braking and electronic anti-skid protection. In addition, for rapid braking, electromagnetic rail brakes are used; these can also be activated separately if required.

Coupled running enables up to four coupled pairs of coaches to be driven from one driver's cab. The control panel resembles that of the DB's standard driving consoles. Safety equipment includes the dead man's switch system, Sifa, which is mandatory in Germany, as well as PZB 90 based on the I60R (Class 628.4) or I60 with ER24 recording device (Class 628.2) and train radio.

Class 628 units have proved to be reliable and economical in practice. Now that newer vehicles have appeared, though, passengers on the 628s will miss a number of refinements, especially air-conditioning, but also modern passenger information systems and easier, more accessible, disabled-friendly doors, because immediately behind the doors (one double or single door in the center and one single door next to each driver's position) there are two steps in order to reach low platforms. On some 628s, new passenger information systems with automatic announcements and displays for the next stop have been installed and in many regions ticket machines have also been fitted, as had been planned in the design.

Over the years the vehicles have not been completely free of technical problems, but the list of deficiencies is very short. For example, the coolant has a tendency to overheat on hot days if the radiators are not thoroughly cleaned. When traction conditions are poor, the 628 may not reach the speeds required by the timetable due to its low adhesive weight. Because the vehicles by today's standards are quite underpowered, its use on hilly routes results in long journey times. On newer vehicles, such as the Desiro (642), the Talent (643 and 644) or the LINT (648), which have partly replaced the 628s, two power cars have been used and the higher resultant costs accepted. Single-unit class 650 (Regio-Shuttle) has received two engines, so all axles are powered.