The Baureihe E 40 is a German
Standard electric locomotive {{Unreferenced, date=June 2019, bot=noref (GreenC bot)
Einheits-Elektrolokomotive (translates as standard electric locomotive) is a German railroad term for the Class E10, Class E40, Class E41 and Class E50 locomotives that were commissioned ...
(German: ''Einheits-Elektrolokomotive'') commissioned by the
Deutsche Bundesbahn
The Deutsche Bundesbahn or DB (German Federal Railway) was formed as the state railway of the newly established Federal Republic of Germany (FRG) on 7 September 1949 as a successor of the Deutsche Reichsbahn-Gesellschaft (DRG). The DB remaine ...
in 1955, designed for
freight train
Rail freight transport is the use of rail transport, railroads and trains to transport cargo as opposed to human passengers.
A freight train, cargo train, or goods train is a group of Railroad car#Freight cars, freight cars (US) or goods wagon ...
s. Since the 1968 renumbering, it is listed as Class 140 and Class 139.
Development
In 1950, the
Deutsche Bundesbahn
The Deutsche Bundesbahn or DB (German Federal Railway) was formed as the state railway of the newly established Federal Republic of Germany (FRG) on 7 September 1949 as a successor of the Deutsche Reichsbahn-Gesellschaft (DRG). The DB remaine ...
introduced two general types of electric locomotives with standardised components: A twelve-wheel (UIC: Co'Co') freight train locomotive as successor for the
class E 94 and an eight-wheel (UIC: Bo'Bo') general purpose electric locomotive as successor for the
class E 44. A new feature was that the driver was seated, whereas formerly they had to stand.
During the construction period the speed requirement for a general purpose locomotive (working title E 46, then changed to
class E 10) was increased to that point that the layout was one for an express train locomotive. Two types were not found sufficient to cover all needs, so the
Einheits-Elektrolokomotiven program was changed to four general types: Light passenger train locomotive (
class E 41), express train locomotive (
class E 10), freight train locomotive class E 40 and heavy freight train locomotive (
class E 50). All four classes were designed to share as many components as possible.
Production and design of Class E 40

The class E 40 basically is a class E 10 without electric brake, altered gear ratio for lower speed and correspondingly higher
tractive effort
As used in mechanical engineering, the term tractive force can either refer to the total traction a vehicle exerts on a surface, or the amount of the total traction that is parallel to the direction of motion.
In railway engineering, the term tr ...
along with additional minor changes.
As all other types of the ''Einheitslokomotiven'' program the class E 40 had welded bogies with central pins. Instead the formerly used axle hung motors it used a
quill drive
A quill is a writing tool made from a moulted flight feather (preferably a primary wing-feather) of a large bird. Quills were used for writing with ink before the invention of the dip pen, the metal- nibbed pen, the fountain pen, and, eventually ...
with a circular rubber spring as a connecting element ("Gummiringfeder" in German) reducing unsprung mass. The control unit had 28 power settings.
879 units were built, making it the ''Einheitslokomotive'' (standard locomotive) of its era.
The original speed was 100 km/h, this was enhanced to 110 km/h in 1969 in order to allow better usability also for
commuter trains. A sub-series, known as 140.8, were equipped for
push-pull train operation.
In 1968 class E 40 was renumbered to class 140.
Subclass E 40.11
Starting in 1959, 31 locomotives were equipped with electrical brakes (as all class E 10 units were) for the ramp near
Erkrath-Hochdahl between
Düsseldorf
Düsseldorf ( , , ; often in English sources; Low Franconian and Ripuarian: ''Düsseldörp'' ; archaic nl, Dusseldorp ) is the capital city of North Rhine-Westphalia, the most populous state of Germany. It is the second-largest city in ...
and
Wuppertal
Wuppertal (; "'' Wupper Dale''") is, with a population of approximately 355,000, the seventh-largest city in North Rhine-Westphalia as well as the 17th-largest city of Germany. It was founded in 1929 by the merger of the cities and to ...
and the
Höllentalbahn in southern Germany. Nowadays these engines are in service around
Munich
Munich ( ; german: München ; bar, Minga ) is the capital and most populous city of the German state of Bavaria. With a population of 1,558,395 inhabitants as of 31 July 2020, it is the third-largest city in Germany, after Berlin and Ha ...
, with recent services to Austria, where the electric brake is very useful. In the beginning of the 1990s some additional class 139 (as they were renumbered in 1968) were built by equipping class 110 units with class 140 bogies and gearboxes from class 110 units pulled out of service.
Both class 140 and class 139 are being replaced by newer constructions such as
class 145,
class 185 and
class 189. It is widely expected that the last units will be scrapped before 2010, though the higher than expected increase in railway freight traffic has created some traction shortages, thus some class 140 units are being overhauled.
External links
E 40 profile and pictures on Trainspo
{{German electric locomotives
E 40
Electric locomotives of Germany
15 kV AC locomotives
Bo′Bo′ locomotives
AEG locomotives
Brown, Boveri & Cie locomotives
Henschel locomotives
Krauss-Maffei locomotives
Krupp locomotives
Siemens locomotives
Railway locomotives introduced in 1957
Standard gauge locomotives of Germany
Freight locomotives