NAG railcar transmission
The NAG railcar gear was a compact mechanical semi-automatic transmission, which for the first of the Deutsche Reichsbahn used benzene mechanical railcar was used. It was suitable for smaller engines with an output of around 55 kW. In the meantime, the transmission has been further developed via the TAG transmission up to the Mylius transmission, which was still used after 1945 .
In contrast to the practice of gear shifting used in automobile construction, the first internal combustion railcars required a greater torque for their mechanical power transmission. In order to keep the gearbox wear within limits, the Deutsche Reichsbahn decided on a gearbox for its first railcars in which the gear pairs to be shifted were constantly in mesh.
The transmission appeared for the first time in 1925 with the four-speed change gear WG 70 from the National Automobile Society for the railcars of the 701-704 series and was then used in around 100 single or twin-engine railcars. It is not known to be used by private railways in Germany.
The transmissions in the narrow-gauge railcars CVE VT 1 and VT 2 had a special field of application . When the vehicles were converted to newer drive motors, the transmission configuration was retained and was used until it was retired. No premature gear change is known from the other known vehicles with these transmissions. The reason for the retirement of the vehicles was the outdated equipment of the vehicles with gasoline engines .
Structure and mode of operation
With this gearbox configuration, the motor is directly connected to the gearbox via a cardan shaft. As with all semi-automatic gearboxes, the shifting process is not actuated directly by the driver, but the shifting is done with pneumatic control. The gear shift could only be carried out when the drive switch was in position 0 or 1 , which prevented switching on at full power.
In this gearbox, the gear pairs to be shifted were constantly in mesh. The respective gear was preselected by the engine driver, and the relevant gear was shifted smoothly using friction clutches controlled by compressed air and actuated by rods. The clutch shoes consisted of a specially impregnated fabric, which means that the gear meshes smoothly when worn. In addition, all gears and the clutches of the second to fourth gears ran in an oil bath. The clutch of the first gear was designed to be particularly strong and was located outside of the actual gearbox housing for better heat dissipation, it was housed in an extra housing with extra cooling fins.
The reversing gear was driven by a short cardan shaft from the output shaft of the gearbox . It was also switched pneumatically. Since the shift could only take place at a standstill, the arrangement with laterally displaceable gears was left with him. For all maintenance work on the gearbox and the reversing gear, flaps were arranged in the floor of the car. The drive axle (s) was driven from the reversing gear via cardan shafts and bevel gear axle drives . The gear housing was supported on the one hand on the drive axle and on the other hand guided by a torque support . This was freely stored in sliding blocks so that the respective axis could adjust to the curve radius.
Vehicles equipped with the transmission for delivery
The following vehicles were equipped with the transmission from the factory:
- DR series 701 to 704, two-axle benzene-mechanical railcars from 1926,
- DR 713/714 and 715/716 , two-axle benzene-mechanical double railcars from 1925,
- DR 755 to 756 , four-axle benzene-mechanical railcars with double engine system from 1926,
- BBÖ VT 10 , a two-axle benzene mechanical railcar of the BBÖ from 1925,
- CVE VT 1 and VT 2, four-axle railcar of Luxembourg Schmalspurbahnen ( Chemins de Fer à Voie Etroite (CVE))
- Heinz R. Kurz: The railcars of the Reichsbahn types . EK-Verlag, Freiburg 1988, ISBN 3-88255-803-2
- Ed Federmeyer: Narrow Gauge Railways in Luxembourg. Volume 2, (= GAR-Documentation), Luxembourg, ISBN 3-921980-46-1
- Heinz R. Kurz: The railcars of the Reichsbahn-Bauarten , EK-Verlag, Freiburg 2013, ISBN 978-3-88255-162-4 , page 27
- Ed Federmeyer: narrow-gauge railways in Luxembourg. Volume 2, (= GAR-Documentation), Luxembourg, ISBN 3-921980-46-1 , page 396
- Ed Federmeyer: narrow-gauge railways in Luxembourg. Volume 2, (= GAR-Documentation), Luxembourg, ISBN 3-921980-46-1 , page 402
- Ed Federmeyer: narrow-gauge railways in Luxembourg. Volume 2, (= GAR-Documentation), Luxembourg, ISBN 3-921980-46-1 , page 399
- Heinz R. Kurz: The railcars of the Reichsbahn types . EK-Verlag, Freiburg 1988, ISBN 3-88255-803-2 , page 22