DR 709 to 712
| DR 709-712 | |
|---|---|
 Factory photo
|
|
| Numbering: |
DRG : 709-712, DB : VT 86 903 |
| Number: | 4th |
| Manufacturer: | Waggonfabrik Gotha |
| Year of construction (s): | 1926 |
| Retirement: | 1947 |
| Type : | A1 dm |
| Genre : | CvT |
| Gauge : | 1435 mm ( standard gauge ) |
| Length over buffers: | 13,600 mm |
| Width: | 2,980 mm |
| Fixed wheelbase: | 7,000 mm |
| Empty mass: | 21,800 kg |
| Service mass: | 27,600 kg |
| Top speed: | 60 km / h |
| Installed capacity: | 55 kW (75 PS) |
| Wheel diameter: | 1,000 mm |
| Motor type: | NAG KL 10 Z |
| Motor type: | Six-cylinder four-stroke petrol engine |
| Rated speed: | 950 rpm |
| Power transmission: | mechanically |
| Brake: | Compressed air brake type Knorr |
| Seats: | 44 |
| Classes : | 3. |
The DR 709 - 712 railcars were delivered in 1926 and are among the first DRG railcars with a mechanical transmission.
They were the design variant of Waggonfabrik Gotha and already had technical features of the diesel-mechanical railcars produced up until the 1950s: transmission wheels of the four gears constantly engaged and electro-pneumatically shifted with claw gears , gear changes after disengaging the single-disk dry clutch . The distinguishing feature of the previous design is the design with a central entry area in the retracted design.
One vehicle in the series was fitted with a diesel engine in 1934. This railcar was in use at Kahlgrund Verkehrs-GmbH (KVG) until 1975 . One vehicle in the series has not survived.
history
Another series of railcars of the first generation were the vehicles of the series DR 709 - 712 , which were built in 1926 in the Gotha wagon factory and the Reichsbahndirektion Oldenburg / O. were handed over. The stationing of the vehicles changed several times. Bremen , Oldenburg and Rheine are named as locations .
They had the same difficulties as the other vehicles of the first generation of railcars, which could not show satisfactory operating results anywhere. Particularly difficulties were mentioned with the machine support frame, the wheel sets, the reversing gear and the torque arms . The car 712 in 1934 tentatively with a hydrogen engine of Junkers equipped. The vehicle was tested with this engine for around 1,000 km in Dessau for a year . There are no records of the test results.
Operating results are available from the 709 . He covered a total of 625,000 kilometers between 1926 and 1941. That's 41,600 km a year or 3,500 km a month. During this time, eight official railway inspections were carried out in the repair shop with an average stay of 56 days.
In 1934 the 710 was converted into a diesel multiple unit with the designation DR 820 . This vehicle was in service with the Kahlgrundbahn until 1975. The remaining vehicles were converted into vehicles with liquid gas drive in 1939 and used in travel during the war. The 711 and 712 were destroyed in the war. The 709 experienced the end of the war with severe damage. The designation VT 86 903 was intended for him . In 1947 the vehicle was taken out of service.
Memories of the railcar series exist only as photographs or as a model.
Constructive features
The vehicles were very similar to the DR 705 to 708 railcars . The car body was designed according to the so-called heavy construction. The car body, which was designed as a steel box frame with riveted sheet steel cladding, was placed on the 12,200 mm long riveted underframe. The 2,980 mm wide car body was drawn in at both ends to 2,252 mm. The car body was identified by the indented middle entry area. At the front there were driver's cabs, which were separated from the passenger compartment by sliding doors. The driver's cab at the rear in the direction of travel could be used as luggage space. That is why the driver's cabs were provided with doors on both sides with bars on the windows. In contrast to the DR 705 to 708 series , the vehicles had neither a protruding barrel roof nor sun protection screens. Another distinguishing feature were the fans for the engine cooling water placed on the roof.
The engine KL 10 Z of the National Automobile Society was mounted with the gearbox in a separate engine support frame. In contrast to the DR 705 to 708 , the manual transmission was not supported on the axle, but rather placed on the engine support frame. In this manual transmission, all gear pairs were constantly in mesh, the gears were shifted by means of compressed air control via claws. It is not clear from the literature whether the switching process was triggered by preselecting the relevant gear or by switching over after the clutch was disengaged. The connection to the drive axle was realized via a combined axle reversing gear, which was controlled by the gearbox via a cardan shaft.
Conventional vehicles were used as reinforcement cars.
literature
- Heinz Kurz: The railcars of the Reichsbahn design. EK-Verlag, Freiburg 1988, ISBN 3-88255-803-2 .
Web links
Individual evidence
- ↑ a b c d e f Heinz Kurz: The railcars of the Reichsbahn types. EK-Verlag, Freiburg 1988, ISBN 3-88255-803-2 , page 31
- ↑ Photo of a model of the 710
