Light steel wagon (SBB)
The light steel wagons were a type of wagon of the Swiss Federal Railways (SBB). The 25 to 30- ton four-axle light steel wagons shaped the image of SBB from the 1930s to the 1990s. A good 1000 lightweight steel cars were built.
prehistory
development
The global economic crisis of the thirties of the 20th century led to a rethink in the construction of passenger cars . At the time, heavy steel wagons weighing 40–45 tons were common. The number of seats was around 40–80, depending on the class. After 1932 there was a big decline in rail traffic. Countermeasures in all areas had to be taken at the Swiss Federal Railways. The profitability of the company had to be increased. In particular, the onset of car traffic and with it the appearance of the first coaches slowly took away additional passengers from the railways.
In passenger transport , the timetable was compressed and the heavy passenger trains were loosened up, which led to many and long stops. Due to the terrain , the SBB network is very winding, which results in many speed restrictions. The SBB hoped that lighter passenger cars would have a favorable effect on travel times. You can accelerate faster with less weight. Because of the lower axle pressure , higher cornering speeds can be permitted. This can reduce the travel time considerably in some cases. At that time, however, the principle was that good driving comfort could only be guaranteed through a correspondingly large weight ( inertia ).
In 1932, the SBB's train transport and workshop service commissioned the Swiss Federal Railways to carry out a study for a new series of wagons with a reduced wagon weight compared to the heavy steel wagons that weighed 40-45 t, a 5 km / h higher cornering speed with the same or improved comfort Wagons and elevator factory (SWS) in Schlieren . With the order, a basic concept was presented by the upper engine engineer of the SBB, Walter Müller, and his section head for wagon construction, Fritz Halm. They were able to convince the SWS, in particular the technical director Karl Füchslin and the chief designer Robert Müller, with their idea. Karl Füchslin carried out the static calculations , which was time-consuming work at the time. Robert Müller was the designer.
The 80-seat third-class car was not allowed to weigh more than 25 tons. This requirement was considered to be extremely futuristic for the time. The weight reduction must not affect the solidity of the car. Because of the increasing amount of car traffic, no deterioration in travel comfort could be permitted; an improvement was even desired. At a time when wagons consisted of a frame with a box built on it, the demands seemed utopian. That is why there was criticism from various quarters. But the risk was successful and the light steel wagons were a complete success. In 1935 the body of the first prototype was completed. When the pre-series model was first used after the timetable change in 1937, it became apparent that all requirements were met or even exceeded. The light steel wagons had a top speed of 125 km / h on delivery. On January 1, 1969, this was increased to 140 km / h. Light metal wagons with open platforms for branch lines, on the other hand, had a top speed of 100 km / h.
The concept of light steel wagons formed the basis of wagon construction for the Swiss railways, and this until the 1970s. After the Second World War , many Swiss normal and narrow-gauge railways needed to renew their rolling stock. The concept of consistently adhering to the light steel construction - actually one has to speak of wagons in light steel construction, light steel wagons is factually the wrong expression - was used next to the SBB for most normal or narrow-gauge railways. As a result, based on the same concept, the standard coaches for Swiss railways were created. The light steel wagons of the SBB were built in a total of 1163. From 1983 onwards they were scrapped. This was completed in 1998 for the passenger cars, some baggage cars continued to run until 2001.
Light express trains with heavy rolling stock
On May 15, 1936, the SBB introduced the two train pairs 5/27 and 6/27 between Zurich and Geneva . The first light steel wagons were still under construction at the time. These trains had shorter travel times and only stopped in Bern and Lausanne . Compared to around five hours, the travel time has been reduced to just 3 hours 25 minutes. The average speed between Geneva and Lausanne was 97 km / h. The cruising speed over the entire route was 84 km / h. These travel times were achieved by the measures listed below:
- Increase in the top speed to 110 km / h (by increasing the v max for the Ae 3/6 I from number 10637 to 110 km / h)
- Increase in cornering speed by 5 km / h
- Reduction of the train weight to 150 t for the purpose of faster acceleration after the speed limit
This was the birth of the so-called city express trains , at that time still referred to as light trains or light express trains . A composition composed in this way was not allowed to exceed a total weight of 150 t with the trailer load . The trains were put together from the latest heavy steel wagons.
The train consisted of a four-axle car B4ü , two four-axle C4ü and a three-axle baggage car F3ü . The braking system had to be adapted for these special applications . The brake pressure was increased from 5 at to 6 at. The studio des Charmilles in Geneva developed, the R-brake (R = Rapid), which at a speed above 80 km / elevated h Klotz pressure generated and the same at a speed below 40 km / h again reduced since otherwise the risk of sliding the Wheels would exist. With this device, the braking distances could be shortened by almost 15 percent. Adjustments also had to be made to the carriage because of the higher speeds. The cradle pendulums of the B4ü were shortened to 300 millimeters and hung at an angle and the side play was enlarged to 45 millimeters. The axle bushing guides of the C4ü had to be replaced with a new version in order to reduce wear. On most of the cars, the inclination of the running surface of the wheelsets was re-profiled to 1/40 instead of 1/20. Test drives between Schlieren and Wettingen showed that the measures taken were correct and that nothing stood in the way of operational use.
It was considered necessary to run a restaurant, but an additional dining car could not be carried due to the limited train weight. The passengers were therefore fed from a kitchen at their seats. This was located in a separate area of the F3ü baggage cart on an area of 2.1 x 2.7 m. The quite extensive kitchen facilities were fed directly from the 220 volt tap of the locomotive transformer via a flying line . The rather dangerous system was later replaced by a 1000/220 volt transformer under the floor of the car, which was supplied with electricity via the heating cable .
The concept of these trains was a success. The trains were already fully occupied on the third day after commissioning, without any decrease in traffic on the other trains. Between Zurich and Bern, another C4ü and sometimes even a BC4ü had to be provided, at the risk of exceeding the total weight of 150 t.
Convinced by the concept of these city express trains, the SBB therefore decided in a daring step not to use the light steel wagons that were being developed for local transport, but for the formation of such express trains.
technology
When the timetable changed in June 1937, the first eight lightweight steel cars were put into operation. There were five third-class cars (the prototype C4ü 9601 and the pre-series types C4ü 9602-9605 ), two second-class cars ( B4ü 4101-4102 ) and the buffet car with third-class compartments ( Cr4ü 10001 ). They were used from the outset on the pair of city express trains 6/27 Zurich – Geneva – Zurich. The train was led by an Ae 3/6 I 110 . They replaced the heavy wagons of the light express train from 1936.
With the train weight of 150 tons specified for the train type, one or two more cars could be set due to the lower car weight, which had an effect on the available space. Light steel baggage / mail wagons were not available at this time. Therefore, as with the light express trains with heavy wagons, an available F3ü was used again. A provisional post office facility was built into it. The light steel wagons were also used on trains 210 and 215 Basel –Lausanne – Basel via Delémont .
Basic principle
The specification was extensive. It is therefore not surprising that the preparatory work and testing took a long time. Five years passed when the order was placed in 1932 and commissioned in 1937. Since completely new territory was broken with the construction of these wagons, it can be said that it was an absolute masterpiece of everyone involved to develop a concept that would shape the construction of railway wagons in Switzerland for decades.
Weight reduction
The heavy steel wagons were all riveted. The consistent use of welding technology has already significantly reduced the weight. But this saving was not enough. The automotive industry served as a model. Here one had switched to the construction of self-supporting bodies . With this measure, the chassis could be dispensed with. The carrying function of the heavy steel wagons was taken over by a heavy underframe. The box built on it with its skeleton had only a small static influence.
The fundamental innovation with the lightweight steel wagons was that there was no underframe. The whole car was a self-supporting, more or less rectangular tube. All box parts (floor, side and end walls and roof) formed a supporting structure that appeared as a whole. In addition to doing without the underframe, the significantly greater static height also led to a considerable reduction in weight. Innovative welding techniques and the general use of, wherever possible, lighter materials also led to considerable weight savings. Compared to the existing wagons, a weight of 25 t (prototype) or 27–29 tonnes (pre-series and series vehicles) resulted in savings of 27 percent compared to the welded and 36 percent compared to the riveted construction, and this despite a two meter larger construction Length.
The French Northern Railways followed similar paths from 1928 onwards, but not to this great extent. Swiss industry and SBB can therefore be seen as pioneers in the extremely lightweight construction of passenger cars. In addition to the exceptionally economical use of raw materials, other components were also carefully examined. A new bogie was developed which, in addition to the lightweight design, also contained hollow axles and wheels with thinner, corrugated wheel discs.
Structure and body
The design of the floor plan was influenced by applications in France . For suburban traffic in Paris, cars were used that had entrances with double doors in the third points. This enabled a better distribution of the entrances over the entire train. This concept was adopted because the new wagons were primarily intended to replace the existing two and three-axle passenger trains. It was not planned at the time that the cars would only appear in regional traffic 30 years later.
The arrangement in the third points also made it possible to lower the height of the car floor in the area of the entrances, which was beneficial for comfort when boarding, since at that time the platforms of the Swiss railways were not very high. Many stations in the country even had no platforms at all. With this lowering of the car floor, a step in the middle could be saved. The central area of the car was at the same height as the boarding platforms; the end areas could be reached via short ramps, as they had to be made about 10 centimeters higher because of the bogies with their wheel sets and to accommodate the pulling and pushing devices. Another ramp was located at the ends of the car, as the internationally standardized height of 1,210 millimeters had to be adhered to for the car crossings. These measures also made it possible to reduce the height of the car by around 150 millimeters.
The third arrangement also had the advantage that the bogies could be placed far outside at the ends of the car. This increased the “guided length” of the car, which, according to the findings of the time, resulted in a smoother run. The lower center of gravity achieved by the low construction had a further influence on the smoother running of the car. The equality of the cars for the third and second class was considered important. That is why both types of wagons in the pilot series had a length over buffers of 22,700 millimeters. End areas, window widths and platforms had the same dimensions. The car types were also equipped with the same bogies. The only difference was in the distance between the windows, as the seat width on the B4ü cars was 1'909–1'919 millimeters, but on the C4ü cars it was 1'700 millimeters. This is why the C4ü has one more window in the middle area than the B4ü. There were further differences in the comfort equipment between the B4ü and C4ü cars. The platforms in the third points enabled a clear separation of the non-smoking and smoking compartments, with the smoking areas at the ends of the car. The tripartite division also had advantages for individual ventilation and heating. With regard to the planned mixed second and third class BC4ü cars, there was also the advantage that the boarding conditions - with corresponding external addresses for smokers / non-smokers - could be regulated more easily. The arrangement could also be used for the central installation of a buffet compartment. Analogous to the Cr4ü buffet car, the C4ü 9602-9605 cars were later converted to such.
The reduction in air resistance was another criterion in the specifications . The car ends have been so easy angepfeilt (outside much because of the location of the bogies, this was not here as a matter of compliance with the clearance profile as in the so-called Hechtwagen ). Care was also taken to arrange the side doors as flush to the outside as possible (except for the prototype C4ü 9601). The same was true of the windows. The operational design of the side doors caused the greatest problems and many different variants were tried out and some were used afterwards. Another important feature of the light steel wagons, again with the exception of the prototype C4ü 9601, was the extension of the car body beyond the buffer beam in order to reduce the turbulence zones in the air. The car bodies were painted in the standard SBB green. The bogies and the underbody were painted gray. The roofs were colored aluminum. The outer doors were made of aluminum and left in their natural color.
Car body
The main difficulty in building light wagons was the construction of the car body. It should be as light as possible, but still be able to absorb the forces that occur during operation. Furthermore, passengers had to be largely protected in the event of derailments or collisions. The box construction was chosen so that the side walls and the roof construction were also included as supporting elements. The heavy underframe with the massive longitudinal beams and - especially in the case of older constructions - beams could be dispensed with. The floor, walls and roof, appropriately stiffened , formed a square tube. The construction had great strength in every direction . The resistance force in the event of an accident is elastically absorbed by the entire structure . A subsequent plastic deformation can take place without splintering. The protection of travelers was thus better than in older cars.
The ordinary steel St 37 was used, which had already been used for the heavy, welded steel wagons. The arc welding , which was new at the time, allowed the use of much thinner steel sheets. This enabled further weight savings to be achieved. Through the possible with the new welding technology blunt compounds also was rust security increased substantially since been prevented from rust by water flow through the virtual absence of overlaps education. The alloy of the steel, which contained 0.3 percent copper , also served for additional rust protection .
The calculation of the box was new territory at the time. For this reason - after individual tests - an experimental box was built in 1935. This was later used for the prototype C4ü 9601. The Bridge Construction Section of the SBB General Directorate played a key role in the experiments, as the principles applied were very much based on bridge construction. The outer skin of the box was made of 2 mm thick steel sheets. These were stiffened by longitudinal and transverse ribs. The weight was only 7 tons. The predecessors weighed in at 14 tonnes and were 2.30 meters shorter. The evaluation of the results of these tests was used to develop an approximate calculation method for the other wagons.
Because of the good results from the tests, the concept was basically adopted for the planning of the other cars. The sheet metal of the outer skin was chosen to be a little thicker at 2.5 millimeters in order to be able to use the stiffeners more sparingly. For this reason, the standard version had smooth side walls and also rounded windows at the bottom. The prototype C4ü 9601, with its ribs in the side walls and the angular windows below, was still very reminiscent of the old heavy-duty steel wagons. A thickness of 1.5 millimeters and 2 millimeters, respectively, was chosen for the roof and floor panels. The ends of the box were no longer so strongly swept. In the standard models, the boxes were also given an overhang over the buffer beam in order to reduce the turbulence in the air. Associated with this was a better visual appearance that conveyed the shape of an entire train instead of individual, assembled cars. The measures taken increased the weight - depending on the type of wagon - to 27–29 t.
Bogies
In principle, the same was leaf spring - bogie SWS taken II, which had been used for the last heavy steel cars. However, a considerable weight reduction had to be made here too. The result is the SWS II L bogie. With the weight reductions described below, it was possible to reduce the weight from 5.5–6.5 tons to around 3.5 tons:
- Bogie frame
- Rotating pan
- side box supports
- Cradle handlebars
- Brake linkage
- Lighting dynamo with cardan drive
The use of wheel sets with hollow shafts and thinner, double-corrugated wheel disks had a significant impact on the book . Compared to the previously used wheelsets with a weight of 1150 to 1250 kilograms, these only weighed 650 kilograms.
Building on this basic type, further types of bogies were developed during the long construction period (20 years) of the lightweight steel wagon. One of the most important changes was the introduction of torsion bar suspension in the secondary spring stage . The use of torsion bar suspension in the primary spring stage had not proven itself and was therefore not pursued any further. In the secondary spring stage, coil springs were also used in some cases .
commitment
The first light steel car, a C4ü (third class car), was delivered in 1937, the series delivery took place in 1939. Most of these cars were built in the late 1940s and early 1950s. The last one was put into operation in 1957. It was a control car suitable for the BDe 4/4 II for the direct current line Geneva – La Plaine .
.jpg)
In their heyday in the 1940s and 1950s, the Geneva – St. Gallen city express trains consisted of lightweight steel wagons and were very popular with passengers.
First these express trains were pulled by the Ae 3/6 I , whose maximum speed was increased to 110 km / h for this purpose. The Re 4/4 I, ordered for this purpose in the 1940s, with a top speed of 125 km / h were designed in such a way that they harmonized with the light steel wagons. For shuttle trains, the lightweight steel wagons were given the BDe 4/4 multiple units with a matching control car.
With the advent of the Standard Car I at the end of the 1950s, the light steel wagons were pushed into the lower performance categories, but continued to dominate the image of the SBB until the 1990s. In the 1980s and 1990s there was a large wave of scrap. The center entry cars were the first to disappear completely; these were scrapped between 1982 and April 1993. The last non-renovated light steel wagons ran according to schedule until around 1998.
Today, light steel wagons continue to run on some private railways, especially in Lombardy , Italy . However, these have been renovated and have automatic doors. The last lightweight steel wagons used at Thurbo , which also received automatic doors, a new paint job and interior fittings, were parked around 2005/2006 for reasons of age.
Today, SBB Historic maintains a historic city express train with the C4ü prototype and other lightweight steel wagons, which are pulled by the Re 4/4 I 10001 .
Car types
The lightweight steel cars were built for all classes of cars. At the time of their publication, there were still three classes. Pure first class cars were not built, only combined first and second class cars (AB4ü). In addition to second class cars (B4ü) and third class cars (C4ü), there were also second and third class cars (BC4ü). However, there were no three-class cars. In the first AB4ü, delivered in 1944–1949, the (seven) first and second class compartments were built to be the same size, which made it possible to use four of these cars as A4ü (1101–04) from 1951 onwards. The AB4ü delivered in 1951/52 received six smaller second-class compartments, the two first-class compartments were now arranged in the middle of the car for reasons of symmetry.
With the abolition of third class on June 3, 1956, the former third class cars became second class cars and the first and second class cars or compartments, which hardly differed in their interior design, became first class cars.
Light steel cars were also built as control cars , dining cars , baggage cars and mail cars .
In the majority of the light steel wagons, the entrance doors were located approximately at the third points, and the non-smoking compartments were usually located between the doors. The entrances were arranged exactly in the middle of two pneumatic cars built in 1950 . This design, which was also used by private railways, was finally used from 1953 for a simplified and around 10% cheaper center entry car . It was only built as a third-class car and originally intended as a secondary line vehicle, but never used that way.
There were also light steel cars with open platforms (aluminum car body). For reasons of cost and weight, these were designed for branch lines. They were mainly used on the sea metal line . With the 1982 timetable, these cars were withdrawn and only used as reinforcement cars until about 1984. The last car with an open platform was retired in 1990.
The first third-class lightweight steel wagons (C4ü) were not upholstered until the first major overhaul, until then the third class had literally been the "wood class". They then had brown synthetic leather upholstery, later had this already ex works. The red / green upholstery for smoking / non-smoking compartments based on the model of the standard car II was not given to the cars until their second major overhaul in the 1970s.
Trivia
- In addition to ordinary light bulbs for the interior lighting (not fluorescent tubes), the light steel cars of the older generation also had dark blue lights. These were installed on the occasion of World War II so that trains were difficult to spot from the air. They were never removed, so that this “war equipment” could still be admired in the 1990s.
- Due to the shortage of wagons, the noisy and uncomfortable lightweight steel wagons had to take over express train services in the 1990s. In return, you were sometimes allowed to use first-class compartments with a second-class ticket, which, in contrast to the second class (notably the third class at the time), were exceptionally comfortable. In the mid-1990s, due to the lack of modern dining cars, the 50-year-old light steel dining cars even had to be used in the Eurocity trains Zurich – Munich.
- Light steel wagons were also used on the Zurich – Munich connection, which had been equipped with additional steam heating for this purpose (there are quite a few pictures of the Bavarian S 3/6 in front of trains made of Swiss light steel wagons in the Allgäu). Most of the light steel wagons with central entrances (50 85 20-39 000-149) were equipped with an additional heater for 3000 volts direct current so that they could also run to Italy. In this context it should also be mentioned that the Ae 6/6 11501-520 and the prototype Re 6/6 were equipped in such a way that they could also supply heating current to trains from Italian domestic cars; In addition, the prototype Re 6/6 11601–11604 had a second heating socket for 3000 volts alternating current (is also illustrated in the SBB publication about its locomotives and on the cover of the fault book for Re 6/6 of the locomotive staff association).
- Two wagons were given tires upon delivery after the Rorschach-Heiden-Bergbahn had already undertaken corresponding tests with an automobile and later with a railbus- like vehicle in the hope of being able to do without gears from now on . The tire-worn cars had five or four axles per bogie and were used in city express trains. However, they did not prove themselves and were initially used on the steep Vevey – Puidoux-Chexbres route and were later given bogies with steel wheels. After an accident, the second-class car was converted into a company car (medical service), and the first-class car ran on steep routes again in its final years of operation, namely on commuter trains from Einsiedeln to Zurich. (see Pneuwagen (SBB) )
literature
- Karl Emmenegger: The light steel wagons of the Swiss Federal Railways (standard gauge) . Pharos, Basel 1997, ISBN 3-7230-0236-6
- SBB passenger coaches and luggage wagons, published by the General Secretariat of SBB, Bern 1982, Voitures et fourgons CFF, edité par le Sécretariat général CFF, Berne 1982 (bilingual publication, German and French)
- Paul Winter: Our cars, SBB primers, volume 5, Orell Füssli Verlag, Zurich 1961, pp. 54–57
-
Light steel wagon of the Swiss Federal Railways: built by Switzerland. Wagons and elevator factory Schlieren .
Schweizerische Bauzeitung, Volume 110 (1937), Issue 2 (Part 1) (E-Periodica, PDF 1.4 MB)
Schweizerische Bauzeitung, Volume 110 (1937), Issue 10 (Part 2) (E-Periodica, PDF 3.6 MB) - New light wagons from SBB . Schweizerische Bauzeitung, Volume 123 (1944), Issue 20 (E-Periodica, PDF 1.4 MB)
Individual evidence
- ^ Daniel Ammann: The BDe 4/4 shuttle trains on the SBB route Genève – La Plaine. In: semaphor. Classic of the railways. Spring 2015 issue, 11th volume, ISSN 1661-576X
- ^ The first scrapping in December 1982 concerned 20-33 037 (ex 5950), who was involved in an accident in Bern Bümpliz; see Railway Amateur 3/93. Last scrapping according to Railway Amateur 8/93 was 20-33 033 (ex 5946) in April 1993.
- ↑ This is because besides the RIC dining cars (which at that time could not be used mostly due to technical problems) it was the only dining car that could withstand the power frequency of 22.5 Hz of the DB class 218. As a result of this problem, the power supply was adjusted for initially four and later for all EW-IV dining cars so that they can be used.