SBB Be 4/7
| SBB Be 4/7 | |
|---|---|
 Be 4/7 12502
|
|
| Numbering: | 12501-12506 |
| Number: | 6th |
| Manufacturer: | SAAS , SLM |
| Year of construction (s): | 1921 and 1922 |
| Retirement: | March 1966-spring 1976 |
| Axis formula : | (1'Bo1 ') (Bo1') |
| Length over buffers: | 16,240 mm |
| Height: | 4,540 mm |
| Service mass: | 111 t |
| Friction mass: | 74 t |
| Top speed: | 75 km / h / 80 km / h |
| Hourly output : | 1,770 kW (2,400 hp) at 56 km / h |
| Continuous output : | 1'530 kW (2'080 PS) at 60 km / h |
| Driving wheel diameter: | 1,610 mm |
| Impeller diameter: | 950 mm |
| Number of traction motors: | 8th |
The Be 4/7 is an electric bogie locomotive for use on the Gotthard route of the SBB . In contrast to the other locomotives of the first hour, the Be 4/7 did not have a rod drive , but a single-axle drive with spring-loaded drives that acted directly on the drive axles .
prehistory
When the second series of the Be 4/6 12303-12342 was ordered in July 1918 , the SBB decided at the same time to order a new type of locomotive that differed in many respects from the other types of locomotive ordered.
The SAAS company , together with the SLM , offered a locomotive that had no rod drive but a single-axle drive . The proposed drive came from Westinghouse in the USA. The Sécheron company had acquired the license for the exclusive use in Switzerland . Applications, in particular with an output of over 500 kW per wheel set, were not available. Nevertheless, an offer was submitted.
Specification book
The SBB required the industry to meet the following specifications:
- Top speed 75 km / h
- Transport of 300 t trailer load on a 26 ‰ gradient at 50 km / h
- Safe starting on a 26 ‰ incline and acceleration of the same load to 50 km / h in 4 minutes
- three return journeys Lucerne - Chiasso within 24 hours (1,360 km)
- Electric brake to slow down the weight of the locomotive on slopes
- Possibility of multiple control .
Ordering and project planning
The order for the passenger locomotive was placed as follows:
SAAS / SLM : Project planning and construction of the passenger locomotive
In addition to complying with the specification, SBB gave the designers great freedom in working out the designs.
Installation
On October 18, 1921 , the Be 4/7 12501 was taken over by the SBB and used for test drives. This was followed by scheduled missions between Bern and Thun .
technology
The mechanical part
landing gear
The chassis consisted of two bogies . Because of the single axle drive, the frames were designed as outer frames. In each bogie, two were driving axles and one as bites salmon trained barrel axis . The bogie on the locomotive side I also had a running axle designed as an Adam's axle on the inside . This additional axle, which gave the locomotive the asymmetrical axle sequence (1'B1 ') (B1'), was necessary because the static axle load of 18.5 t was not wanted to compensate for dynamic loads from the spring-loaded single axle drive. In terms of the total weight of the locomotive, it was assumed that it would not be smaller than that of a Be 4/6 .
The outer running axles had a side clearance of 2x83 mm, the middle Adam axle a side clearance of 2x57 mm compared to the bogie frame.
Traction transmission
The tensile and impact forces were transmitted from the drive axles to the two bogies. From there, the external forces were transferred to the draw hooks and buffers. Inside were the bogies for tensile and compressive force transmission over a fortified with conical springs of the bogies dome iron connected. In addition, the bogies were connected with two coupling rods that served as emergency couplings. An articulated cross coupling between the bogies improved the locomotive's cornering.
drive
The traction motor housings of the twin or double motors were supported in the bogies on crossbeams and bolted to girders. The torque of each double motor was transmitted to a common large gear via a pinion . This was attached to a hollow shaft , which was stored in the common motor housing and enclosed the drive axis . This hollow shaft drifted over drivers and coil springs the drive wheels to. The driving wheels were dimensioned in such a way that wheel tires of the steam locomotives A 3/5 901-938 of the former Gotthard Railway Company could be used. These locomotives were about to be retired.
Locomotive body
The locomotive body consisted of a continuous bridge with screwed-on box parts without a front end. The locomotive bridge was supported at three points on the two bogies:
- Fixed pivot bearing between the two drive axles of the bogie I.
- Trunnion bearing with longitudinal play between the outer drive axis and the Bissel axis of the bogie II.
- Spring-loaded roller support bearing above the inner coupling of the bogie II.
Tensile and compressive forces were not taken over by the locomotive body. The floor of the locomotive bridge was in the shape of a box. The motors and drive wheels protruded into these. Access to the engines was ensured by covers from above and in the longitudinal walls. A cooling air duct extending the full length of the engine room was bolted to the ceiling of the box.
The locomotive box contained all of the electrical equipment. The transformer was in the middle of the box.
In contrast to most of its contemporaries, the Be 4/7 did not have any side ventilation louvres in the locomotive body, as all ventilation came from the roof.
Braking system
The automatic brake and the regulating brake acted on the drive axles and the inner running axle for each bogie. The outer running axles were unbraked. Each driver's cab had a handbrake that worked on the respective bogie.
Top speed
In the second half of the 1930s, the top speed was increased from 75 km / h to 80 km / h.
The electrical part
Main circuit
The high voltage from the catenary was picked up with two pantographs . From each consumer, the current was fed to the electro-pneumatically operated main oil switch via a cutting knife and a lightning protection coil. From there the electricity goes to the transformer. The transformer oil was cooled using tube bundles that were attached to the cover of the transformer and immersed in the oil. Ventilation air flowed through the tube bundles. The lightning protection coils were later removed because they were not necessary.
The four twin motors were connected in parallel . They received the traction current via a battery of nine electropneumatic individual switches ( hops ). The transformer had 8 taps from 100V to 864V. The 28 speed levels were created by interconnecting the hoppers with an additional transformer and three choke coils .
Each twin engine had a separate reversing switch . The two reversing switches on each bogie were each controlled by a common electropneumatic drive. The reversing switches had the positions "forward", "reverse" and "electric braking". By blocking in the zero position, individual defective twin motors could be separated.
Auxiliaries
The following described, 220 V-operated auxiliaries were located on the locomotive:
- A rotary compressor .
- Two fans. These conducted the cooling air through blinds in the locomotive roof into the engine room, through the ventilation duct to the traction motors, through the oil cooling pipes in the transformer and through the resistance shafts.
- A converter group for battery charging.
- Driver's cab heating and oil heating plates.
The supply of the train heating originally with the voltages 800V, 1'000V and 1'200V was carried out via mutually locked hoppers from the transformer. The voltages were later changed to 600V, 800V and 1'000V. The 600V and 800V levels were expanded at a later date.
Electric brake
As with the Be 4/6 of the second series, a separately excited alternating current resistance brake was used as the electric brake . The above-mentioned additional transformer supplied the excitation current. The control took place via the normal step taps. The energy generated was destroyed in braking resistors, which, unlike the Be 4/6, were not on the locomotive roof, but in shafts on both sides next to the main transformer. Automatically controlled flaps that conducted the ventilation air through the shafts were used for cooling. Some of the braking resistors were used as reversing pole shunt resistors for the traction motors.
Multiple controls
There was never a multiple control with the Be 4/7.
Serviceability
Compared to the clear and maintenance-friendly arrangement of the locomotive box of the Be 4/6 , the box of the Be 4/7 was simply "crammed full".
Even checking a drive motor was an artistic undertaking due to the existing maintenance hatches.
In contrast to the Be 4/6, the batteries were in the locomotive box. On the side of the locomotive box was a screw-off flap. Eyelets were attached to the locomotive roof that allowed a crane runway with a trolley to be attached. It is obvious that changing the battery was not that easy. With the appearance of forklifts , the batteries to be exchanged were usually handed in through a window and placed inside by hand.
Operational use
On October 18, 1921 , the Be 4/7 12501 was taken over by the SBB. It was immediately used as planned for test drives between Bern and Thun . At the end of December 1921, it was postponed for starting attempts on the Gotthard north ramp . It should be proven that it was equal to the Be 4/6 in terms of performance. As part of these tests, she accelerated a test train with a trailer load of 300 t from a standstill to 50 km / h within 2 minutes.
The delivery of all six locomotives was completed in mid- 1922 . At this point in time, all locomotives were stationed in the Bern depot. Her career on the Gotthard began in May 1923 from the Erstfeld depot .
All six machines were in circulation from 1923 to 1928 . Until 1927 they were deployed from the Erstfeld depot, then from the Bellinzona depot . Between 1926 and 1929 , the locomotives covered an average of 112,000 km-132,000 km annually. In the case of the Be 4/6 it was about half, but this should be relativized in that the scheduled daily performance of the Be 4/6 on the Gotthard between Erstfeld and Bellinzona was about the same, especially the continuous trains between Lucerne and Chiasso .
The locomotives were very popular with drivers because they ran extremely smoothly compared to the bumpy Be 4/6. That is why all six locomotives were usually used in the plans.
When the first Ae 4/7 appeared on the Gotthard from May 1928 , the Be machines were gradually moved. In 1930 the numbers 12501-12503 came to District I (western Switzerland) in Lausanne . In 1931 they were transferred to Bern. In the timetable period 1930 /1931, the numbers were 12501-12503 especially on Simplon in toughening and pusher service Domodossola - Iselle in use. They also ran individual freight trains Domodossola - Brig - Domodossola.
In 1932 the 12504 and in 1936 the 12505 and 12506 were transferred to Bern. In 1940 maintenance was transferred from the main workshop in Bellinzona to the main workshop in Yverdon . The Bern depot had a schedule for the six machines that included Basel (via Delémont ), Porrentruy , La Chaux-de-Fonds , Friborg , Thun and Olten . This also included a pair of express trains Basel - Delémont - Basel.
The deposit allocation changed in 1966 . Although they ran together with the Be 4/6 from the Biel depot in a joint plan, they were only assigned to Biel this year.
For maintenance, the locomotives drove to Bern every other day and once a week to Biel. At that time you were around Bern and Biel to Thun, Lucerne (via Langnau ), Friborg, Travers , Le Locle , Porrentruy and Aarau .
The Be 4/7 12503 was the first of its series to be retired in March 1966 due to serious engine damage . In May 1967 the last schedule was drawn up for five Be 4/7 and three Be 4/6. They drove in the action area described above and achieved an average of 237 km per day. In some cases, the Be 4/7 were already in use as stationary transformers for the supply of 220V in substations. These were the number 12503 in the summer of 1965 in Courtemaîche and the 12504 in 1966 in Burgdorf and 1969 in Etzwilen .
The number 12502 was retired in June 1968 after a drive engine failure. It was followed by number 12501 after a fire.
The remaining three Be 4/7 were taken out of service in the spring of 1976 . The number 12504 was retained as an operational locomotive that was largely restored to its original state. 12506 was after staying up in November 1978 in the Museum of Transport also canceled in Lucerne, Switzerland.
It remains to be seen why the SBB did not trigger subsequent purchases of this excellent locomotive. The decision to procure additional Be 4/6 was made because there was time pressure and the single-axle drive had not been tested when the Gotthard locomotives were reordered. That the locomotives would then really prove themselves could not be foreseen at the time of the reorder.
In addition to all the advantages, the greatest weakness of the locomotives was the coil springs of the single axle drive. These broke frequently. For this reason, experiments were carried out with an MFO drive on the 12501 locomotive from 1930 to 1934 . In the 1950s, the coil springs on all locomotives were replaced by rubber blocks. Incidentally, these adjustments were also made to the Ae 3/5 and Ae 3/6 III .
See also
literature
- Hans Schneeberger: The electric and diesel traction vehicles of the SBB, Volume I: years of construction 1904–1955; Minirex AG, Lucerne; 1995; ISBN 3-907014-07-3
- Claude Jeanmaire: The electric and diesel locomotives of the Swiss railways, The locomotives of the Swiss Federal Railways (SBB)
