SBB Ae 4/8

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SBB Ae 4/8
Ae 4/8 11300
Ae 4/8 11300
Numbering: 11000, 11300 (from 1929)
Number: 1
Manufacturer: SLM Winterthur, BBC Baden
Year of construction (s): 1922
Retirement: December 31, 1964
Axis formula : (1'Bo1 ') (1'Bo1')
Length over buffers: 21,000 mm
Service mass: 127 t
Friction mass: 73 t
Top speed: 90 km / h
Hourly output : 1,885 kW (2,560 hp) at 62 km / h
Continuous output : 1,620 kW (2,200 hp) at 65 km / h
Driving wheel diameter: 1,610 mm
Impeller diameter: 950 mm
Drive: Buchli drive ,

Tschanz drive

Drawing of the SBB Ae 4/8 11300

The Ae 4/8 was a prototype locomotive of the Swiss Federal Railways (SBB) procured to test electrical operation . The locomotive was equipped with two different drives - hence the nickname Bastard . Because of the three-part locomotive body , it was also given the nicknames Tatzelwurm and Feldschlange .


During the First World War , the SBB decided to introduce electrical operation on the main lines as quickly as possible in order to become independent of coal deliveries from the warring neighboring countries. Since the technology of electrical railway operation was still new, a suitable locomotive design had to be found first.

The SBB therefore procured several test locomotives. In addition to the locomotives Fb 3/5 11201 , Fb 2x2 / 3 11301 , Fb 2x2 / 3 11302 and Fc 2x3 / 4 with drive via coupling rods , the SBB also procured the test locomotive Fb 2/5 with single-axle drive as early as 1918 . However, this locomotive was too weak and too slow to carry out a test in service. That is why the SBB ordered a second test locomotive with single-axle drive from SLM and BBC as early as 1919 . Like the Fb 2x2 / 3 locomotives, this test locomotive should also have four drive axles . The specifications corresponded to that of the Fb 2x2 / 3, but required a maximum speed of 90 km / h for use in express train service.


mechanical construction

The Ae 4/8 was planned from the start with two more axles than the Fb 2x2 / 3, because it already fully used the axle load of 20 t and the engines of the Ae 4/8 were heavier than those of the Fb 2x2 / 3. In contrast to the Fb 2x2 / 3 bogie locomotive , the Ae 4/8 was designed as a frame locomotive with a three-part locomotive body . The articulated construction allowed good cornering despite the drive motors housed in the locomotive body. Because of its design, the locomotive was also given the nicknames Tatzelwurm and Feldschlange .

The locomotive consisted of three boxes connected by bellows , of which the two end boxes had small fronts. The underframe consisted of two closely coupled frames, each of which had two drive axles , a leading Bissel axle and a trailing Adam's axle . As with the Be 4/7, the frames were connected directly to one another with a spring-loaded drawbar and two emergency couplings. While the end boxes were firmly mounted on the frame, the middle box sat on a bridge which was not involved in the transmission of the tensile and impact forces. The bridge was supported by pivot pins and horizontal springs between the inner drive axes and the Adam axes on the frame.

The transformer was installed in the middle part of the locomotive . To expand it, the roof of the middle section could be removed. The roofs of the outer parts could be extended individually on the right and left. The side elements could be expanded in individual parts. The middle part of the box could be lifted off as a whole. In the porch in front of the cab I were two reciprocating compressors . The front end on the driver's cab side II contained the brake transformer , a sleigh winch and a tool box.

The locomotive was equipped with four identical traction motors that were firmly bolted to the frame . The single axle drives were different for the two frame parts, which is why the locomotive was also called a bastard . Tschanz drives were mounted on locomotive side I, and Buchli drives on locomotive side II . The Tschanz drives used a cardan shaft as an essential feature to transmit the torque between the unsprung gear and the sprung drive axle. In contrast to the version of the Fb 2/5 , the drive axle was not made hollow. The cardan shaft was only passed through the short hollow shaft of the last gear wheel and flanged directly to the outside of the drive axle. One-sided BBC drives (Buchli drives) were mounted on the locomotive side II . Due to the great weight of these drives, however, unlike on the locomotive side I, they were arranged laterally offset. An arrangement of the drive on both sides as in the Fb 2/5 was dispensed with.

The locomotive was braked as follows:

  • Drive axles braked on both sides
  • inner running axles braked on one side
  • outer running axles unbraked
  • one brake linkage per locomotive half
  • automatic air brake with single control valve system Westinghouse .
  • direct acting regulating brake
  • Handbrake in every driver's cab on the associated bogie The Ae 4/8 was never equipped with split brake pads or automatic brake slack adjusters during its entire life .
  • an electric brake was available (see electrical part)

The total weight of the locomotive of 127 t, incidentally the same as the Ae 4/7 built later , distributed over a total of 8 axles, resulted in a maximum axle load of 18.6 t on the drive axles. The limit of 20 t was thus fulfilled. Otherwise, the load distribution on the individual running and drive axles was quite inharmonious, with locomotive part I being characterized by significantly higher axle loads. The axle loads are listed below, starting with the outer Bissel axle of locomotive part I: 14.0 t - 18.3 t - 18.6 t - 14.5 t - 14.2 t - 18.1 t - 17.9 t - 11.2 t

The sand spreading device was therefore of particular importance. Each drive wheel could be sprinkled with sand using compressed air in both directions of travel.

Electric Construction

The electrical part was taken over from the Be 4/6 12303 . The following differences existed:

  • higher power of the drive motors (hourly output 4 × 490 kW instead of 4 X 370 kW)
  • electric brake like Be 4/6 12313 and subsequent ones

The transformer , main oil switch and tap changer were housed in the middle box. The energy supply from the contact line was carried out via the two pantographs on the end box. Initially, both pantographs always had to be lifted during operation, because they were originally only equipped with a simple contact strip without a rocker. The superstructures for the reversible pole shunts and the braking resistors were located in front of the pantographs above the driver's cabs .

The 18-position BBC flat -panel tap changer was located on the transformer and was driven by a battery-powered direct current motor. The step switch was initially controlled by a crank and later by a handwheel. Manual operation of the tap changer was possible, but only inside the tap changer itself.

The transformer oil was cooled via cooling pipes that were arranged on both sides below the middle part of the box. An oil pump was available to circulate the oil. Each of the pipe systems was built into a shaft. A fan each pressed the air drawn in from the inside of the locomotive through these.

The drive motors in the end box were connected in series . The locking of the respective reversing switch allowed one side of the locomotive to be separated.

An alternating current excited resistance brake was used as an electric brake. The braking resistors , cooled by the wind, were located above the two driver's cabs, together with the Wendpolshunts.

The following auxiliary companies were available:

  • two compressors
  • a converter group for battery charging
  • a common fan for the two drive motors with Tschanz drive
  • two fans with a common drive motor for the traction motors with the BBC drive
  • an oil pump
  • Cab heating

Operational use

At the beginning of electric traction, the sight of electric locomotives was still unusual for railway workers. The ventilation grilles were reminiscent of wrinkles, which is why the locomotive was soon nicknamed grandmother .

After delivery in March 1922, the locomotive was first used on the Bern - Thun line, as this was the first SBB line to be electrified with 15 kV 16 ⅔ Hz. However, the locomotive was never used on the Lötschbergbahn from Thun to Brig, as was the case with the test locomotives with rod drives. The locomotive did not live in Bern for long. This was soon followed by a trial phase lasting several years without any schedule, including on the Gotthard route .

In 1925 the locomotive was transferred to the Basel depot . This depot allocation was not changed until the locomotive was decommissioned.

In 1927 there was a duty roster in which the Ae 4/8 and Ae 4/7 were assigned to two pairs of express trains from Basel to Zurich and back with a daily mileage of 416 km. Soon afterwards, the Ae 4/8 disappeared again from the operational plans. With its load norm, which was around 90% of the Ae 4/7, it was universally applicable. With its top speed of 90 km / h, it could also run express trains. It was therefore often used for double tours and in this role often came to Zurich, Chur , Lucerne , Bern and Spiez .

Normally the Ae 4/8 carried freight trains to Bern and Winterthur . In recent years, services from Basel - Zurich - Winterthur followed, followed by the Olten passenger train and the Solothurn freight train . In 1961, new gears were even installed in the Tschanz drives.

On October 7, 1964, a driver reported tap changer rollover. As a result, the locomotive was towed to the main workshop in Zurich. But because of EXPO 64, it had too many other tasks. Therefore the Ae 4/8 was parked for the time being. As the general management of the SBB in Bern had promised to take the veterans out of service after EXPO 64, the Ae 4/8 was canceled immediately.

The technical importance of the locomotive was minor. At the time the Ae 4/8 was delivered, the six Be 4/7 with the Westinghouse drive and the first Ae 3/6 I with the BBC drive were already in operation. The Tschanz drive was no longer built due to its complexity. Amazingly, the last parts of this drive were only scrapped in the main workshop in Zurich in 1967.

The external appearance

The locomotive originally had a brown paint job - like many SBB electric locomotives - which was later replaced by a green one. When it was procured in 1922, it was called Ae 4/8 11000, and in 1929 the company number was changed to 11300. The same number was later given to an SBB Re 4/4 II .


  • 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 traction vehicles of Swiss railways. Volume 5: The locomotives of the Swiss Federal Railways (SBB). 1979, ISBN 3-85649-036-1 .

Individual evidence

  1. ^ K. Sachs: Electric full-line locomotives . Julius Springer, Berlin 1928, DNB  361661592 , p. 309 (footnote).

See also