DR test trains A to F

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The test trains A to F were multiple units that the Deutsche Reichsbahn acquired in 1922 for the electrification of Berlin's city, ring and suburban railways. The trains had different room layouts, which the Reichsbahn wanted to test for the planned operation. In the basic design, however, the trains were largely identical. On August 8, 1924, they started electrical operation on what would later become the Berlin S-Bahn .

prehistory

Wagon numbers
train Manufacturer
(mech.) 		Car no.
(from 1922) 		Car no.
(from 1924) 		Car no.
(from 1930)
A. WUMAG Tw 12001-12004 2051-2054 3001-3004
Bw 12501-12506 5051-5056 6001-6006
B. Uerdingen Tw 12101-12104 2071-2074 3005-3008
Bw 12601-12606 5081-5086 6007-6012
C. vdZ Tw 12201-12204 2055-2058 3009-3012
Bw 12701-12706 5057-5062 6013-6018
D. LHW Tw 12301-12304 2059-2062 3013-3016
Bw 12801-12806 5063-5068 6019-6024
E. WUMAG Tw 12401-12404 2063-2066 3017-3020
Bw 12901-12906 5069-5075 6025-6030
F. WUMAG Tw 13001-13004 2067-2070 3021a, e-3022a, e
Bw 13501-13506 5075-5080 3021b, c, d-3022b, c, d

In 1913, the Prussian state government passed a law that granted the Prussian state railways the means to electrify Berlin's city, ring and suburban railways. The current system used in Germany with 15 kilovolt 16 2/3 Hertz alternating voltage and power supply via the overhead line should be used as the power system . The use of motor frames and compartment cars was intended as operating resources . The First World War delayed the project. When the plans were resumed, an inventory of the measures carried out so far and new profitability calculations led to the decision to electrify the lines with 800 volts DC . Power should be supplied via a busbar attached to the side .

Before the electrification of all routes, the Deutsche Reichsbahn, founded in 1920, wanted to gain experience on a small route network with regard to power supply systems, operational management and driving design. The choice fell on the suburban lines to Bernau , Oranienburg and Velten starting from the Szczecin train station , as these mostly had pairs of tracks that were independent of long-distance and freight traffic . The Reichsbahn initially commissioned six trains that should run instead of the steam trains in the existing timetables. They should provide information about which vehicle variant was most suitable for a quick passenger change , short stays on the platform and thus a short travel time .

construction

Building principles

Common to all trains was the division into four longer railcars and six shorter trailer cars. Two railcars each with three sidecars coupled between them formed the smallest unit called a half-train. The railcars had a Willison coupling at the ends with a driver's cab , and the railcars and sidecars were closely coupled to one another. The railcars were equipped with two bogies , of which the front was powered. The sidecars had two running axles attached to the undercarriage . An exception was the test train F, in which the wagons of a half-train were connected to Jakobs bogies . The train therefore had two axles less and was eight tons lighter than the other test trains.

Mechanical part

The platforms on the three test routes had a continuous platform height of 760 millimeters above the top edge of the rails , so that the wagons with a planned floor height of 1000 millimeters above the top edge of the rails could do without steps. This enabled the vehicle boundary profile to be fully utilized in the lower area. By installing sliding doors , passengers on the platforms were no longer endangered by opening the doors prematurely. However, the Bo'2 ' wheel arrangement chosen for the railcars had a major impact on the design of the vehicles. In order to fulfill the set driving program, the calculations showed that if only one powered bogie was used per railcar, the drive wheel diameter would have to be 1000 millimeters; the diameter of the running axles could be set at 850 millimeters. As a result, the side members in the area of ​​the motor bogie had to be cranked so that the floor of the car could be raised to 1250 millimeters in this part. The compartment above the bogie was separated from the rest of the passenger compartment and therefore not so easy to reach. The difference in height compared to the edge of the platform in turn required the installation of steps so that the car bodies tapered towards the end of the driver's cab. The train drivers therefore had to lean far out of the driver's cab when handling the trains, which increased the time spent at the stations. Another consequence in the chosen axle arrangement was the length of the motor coach and trailer. In order to achieve the necessary minimum friction mass , the railcars had to be around 20 meters long. In view of the existing platform lengths, this resulted in a total length of around 30 meters for the sidecar. A uniform design of motor coaches and sidecars was therefore excluded.

inner space

In contrast to the vehicles previously used on the light rail , the test trains were not designed as compartment cars with partitions that were partially stretched to the ceiling. For the test trains A, B, D and F, the seating was changed from 4 + 0 to 2 + 2 with a central aisle in between. In train C, the 4 + 0 seating was retained, but the benches were staggered, as in the test railcars 531 and 532 , with the door opposite. In train E, lengthways benches were installed similar to the Berlin elevated and underground railway. The compartments behind the driver's cab were separated from the rest of the passenger compartment and had two longitudinal benches and one transverse bench on the partition. The railcars were all 3rd class , the sidecars were 2nd or 3rd class. Three sidecars were mixed 2nd and 3rd class cars. Smoking and non-smoking compartments were distributed over the entire train. The lighting tried and tested in the Lichterfeld railcars was used for the interior lighting. The lamp voltage was 110 volts, with several lamps being connected in series to enable direct power supply from the power rail. Each lamp body had two light bulbs that were switched to four circuits in the drive and two circuits in the sidecar.

Train control

Motor types
Manufacturer Type Number of Tw
WASSEG GBM 1620 9 Tw
BMS BMS 80 6 Tw
BMS GBR 132/725 5 Tw
Pöge Pöge 2 Tw

The greatest attention was paid to the electric train control. The Reichsbahn commissioned two groups of companies to develop the electrical components. On the one hand, this was the WASSEG consortium formed by Siemens-Schuckertwerke (SSW) and AEG , and the BMS consortium formed by Bergmann Elektrizitätswerke and Maffei-Schwartzkopff-Werken on the other . Both groups of companies were required to coordinate their variants in such a way that they could travel in train sets without restrictions. Otherwise, the companies were largely given freedom. Nevertheless, both groups worked closely together. As a result, four different types of motors were constructed in paw-bearing design , each with an hourly output of 170 kilowatts. No details are available for two railcars.

The train control had the task of switching the individual resistors on or off, grouping them and changing the direction of travel . Optional circuits should enable the driver to start at different speeds or to maneuver at walking pace . A contactor control with a step switch would have made this possible, but was ruled out for the test operation due to the individual operation of each driver and thus different driving behavior. Both groups of companies therefore developed an electropneumatic switch drum control in which the driver selects a position using the travel switch crank. The switchgear then switched depending on the motor current so that the substation and drawbars were not overloaded and the drive axles were prevented from skidding. The crank was fitted with a dead man's mechanism . The switching of the shift drum was based on the principle of the series motor . In the forward direction, five shift positions could be selected as continuous speed levels:

  • Position 1: shunting level, shift drum position 1
  • Position 2: Series connection of the traction motors, all resistors switched off, shift drum position 6
  • Position 3: Series connection of the traction motors with field weakening , shift drum position 9
  • Position 4: parallel connection of the traction motors, all resistors switched off, shift drum position 12
  • Position 5: parallel connection of the traction motors with field weakening, shift drum position 15

The drive device at WASSEG was a toothed rack operated by compressed air pistons , at BMS a ratchet mechanism . The switching relay was equipped with a continuously adjustable resistor, which allowed the acceleration to be changed. This was used to determine the most favorable starting acceleration. The fixed values ​​were 0.3 and 0.5 meters per square second. Switching mechanism and latch mechanism were different devices in the BMS motors that were connected to one another via a coupling. The drive mechanism of the WASSEG motors, on the other hand, was built into the switchgear. Other components such as reverser, main contactor and overcurrent relay were built differently depending on the motor type. Several railcars were switched on at the same time via control lines that had to be coupled manually. The lines also served to control the compressed air brake from the leading railcar.

commitment

The individual wagon construction companies delivered the trains ex works without electrical equipment, as this could not be delivered on time due to the late decision in favor of DC voltage. The trains were therefore tested in a train set with steam locomotives on the light rail. In 1924 the Reichsbahn repair shop in Berlin-Tempelhof installed the electrical equipment and cables in the cars. At the end of May 1924, the first test drives began, which also served to retrain the steam locomotive personnel on the new vehicles. On August 8, 1924, electrical operation on the line from the Szczecin suburban railway to Bernau could begin. The electric trains initially ran according to the schedule of the steam trains, as a complete changeover of the route was not yet possible. In order to accomplish this at short notice, the Deutsche Reichsbahn-Gesellschaft ordered a further 34 half-trains, which were based on the test train A in the wagon construction part, before the test runs were evaluated. The cars of the later ET / EB 169 series were therefore already outdated when they were commissioned.

Initially, only two end cars were built from the test train F. After the test drives with these were satisfactory, the remaining cars were designed and the two half-trains put together. The test drives were partly carried out at speeds of over 100 kilometers per hour, with no defects in terms of running properties. The use of Jakobs bogies meant that separating the individual wagons was time-consuming and more expensive than with the other trains. A later installation of a traction motor in the second bogie was also not possible, which is why the concept was not used.

The wagons of the individual trains were initially of the same type, but from 1924 onwards the wagons were interchanged. One reason could have been the inexpedient seating arrangement on trains C and E, which should not be concentrated on one train. The test trains remained in use on the three northern suburban lines until they were retired in 1933/34. The examinations were initially carried out in the RAW Berlin-Tempelhof, from 1927 in the RAW Berlin-Schöneweide . The last investigations took place in 1930/31. The mileage of the individual trains was then less than 3000 kilometers until they were retired.

A railcar from test train C was still used as a gazebo after it was decommissioned . It was scrapped in 1988.

Compilation of trains from 1924
Half move Car no. (from 1924) / test train / car class Retirement Remarks
Tw Bw Bw Bw Tw
1 2051
A
3.		 5054
A
3.		 5073
E
3.		 5056
A
2.		 2053
A
3.		 10/25/1933 Tw 2051 from 11.03.30 on the train
2 2052
A
k. A.		 5072
B
k. A.		 5052
A
k. A.		 5051
A
k. A.		 2054
A
k. A.		 00.00.1933
3 2066
E
3.		 5081
B
3.		 5082
B
2.		 5083
B
2nd / 3rd		 2072
B
3.		 December 18, 1933 Compilation on June 5th, 1926
4th 2071
B
3.		 5062
C
3.		 5085
B
2.		 5086
B
2nd / 3rd		 2074
B
3.		 03/07/1934 Tw 2074 due to Damage several times in 1927 in the RAW Berlin-Tempelhof ;
possibly different order
5 2055
C
3.		 5071
E
3.		 5058
C
3.		 5059
C
2.		 2057
C
3.		 11/23/1933
6th 2056
C
3.		 5060
C
3.		 5070
E
2nd / 3rd		 5084
B
2.		 2058
C
3.		 04.10.1933
7th 2059
D
3.		 5074
E
3.		 5064
D
2.		 5067
D
3.		 2062
D
3.		 December 29, 1933 Tw 2062 from 01/24/1929 on the train,
previously in the half train 8
8th 2061
D
3.		 5069
E
3.		 5063
D
2.		 5065
D
3.		 2060
D
3.		 03/07/1934 Tw 2060 from April 20th, 1929 in the train,
previously in the half-train 7
9 2065
E
3.		 5053
A
3.		 5055
A
3.		 5068
D
2.		 2073
B
3.		 December 29, 1933 From 14/09/1928 to 04/03/1929 in RAW Berlin-Schöneweide off
10 2063
E
3.		 5057
C
3.		 5061
C
3.		 5066
D
2.		 2064
E
3.		 02/21/1934
11 2067
F
3.		 5075
F
3.		 5076
F
3.		 5077
F
2.		 2068
F
3.		 01/21/1934
12 2069
F
3.		 5078
F
2.		 5079
F
3.		 5080
F
3.		 2070
F
3.		 01/26/1934

literature

Web links

Individual evidence

  1. ↑ a b c d e f g h i j k l m n Hans-Joachim Hütter: The first electric test trains for the Berlin S-Bahn . In: Verkehrsgeschichtliche Blätter . Volume 4, 1984, pp. 75-81 .
  2. ↑ a b c d e Michael Dittrich: The test trains A to F - type 1922. In: stadtschnellbahn-berlin.de. October 26, 2008, accessed July 7, 2016 .
  3. ^ Bernd Neddermeyer: The electrical operation on the Berlin S-Bahn. Volume 1: Steam or Electricity? 1900 to 1927 . VBN Verlag B. Neddermeyer, Berlin 1999, ISBN 3-933254-05-1 , p. 103-113 .
  4. ↑ Michael Dittrich: The series 169 - design 1924 (Bernau). In: stadtschnellbahn-berlin.de. January 24, 2009. Retrieved July 24, 2016 .
  5. ↑ Vehicle database from www.stadtschnellbahn-berlin.de. In: stadtschnellbahn-berlin.de. Retrieved July 24, 2016 .