Crocodile (locomotive)

Crocodile (German Krokodil) electric locomotives are so called because they have long "noses" at each end, reminiscent of the snout of a crocodile (see also Steeplecab). These contain the motors and drive axles, and are connected by an articulated center section. The center section usually contains the crew compartments, pantographs and transformer.

Swiss "crocodile" locomotive
Dimensions are for Be 6/8II
version - an upgraded Ce 6/8II[1]
Crocodile Ce 6/8II on display in Erstfeld[2]
Type and origin
Power typeElectric
BuilderSwiss Locomotive and Machine Works
and Maschinenfabrik Oerlikon
Build datebuilt 1919 to 1921
rebuilt 1942 to 1947
 • AAR1-C+C-1
 • UIC(1′C)(C1′)
Gauge1,435 mm (4 ft 8 12 in) standard gauge
Wheel diameter1,350 mm (53.1 in)
Trailing dia.950 mm (37.4 in)
Wheelbase16,500 mm (54 ft 1 58 in)
Length19,460 mm (63 ft 10 18 in)
Adhesive weight103 long tons (105 t; 115 short tons)
Loco weight126 long tons (128 t; 141 short tons)
Electric system/s15 kV  ​16 23 Hz AC Catenary
Current pickup(s)Pantograph
Traction motors4 single-phase commutator type
Transmissionjackshaft and side rods
Performance figures
Maximum speed75 km/h (47 mph))
Power output(1 hour rating) 2,721 kW (3,649 hp)
at 45 km/h (28 mph)
Tractive effort(30,000 kgf (66,000 lbf)
Official nameBe 6/8

The name was first applied to Swiss locomotives. Sometimes the term is applied to locomotives in other countries of a similar design.



Class Ce 6/8Edit

A prototype locomotive, SBB-CFF-FFS Ce 6/8 I number 14201, was ordered in June 1917. The production "Crocodiles" were the series SBB Ce 6/8 II and SBB Ce 6/8 III locomotives of the SBB, Swiss Federal Railways, built between 1919 and 1927. There were 33 class Ce 6/8 II and 18 class Ce 6/8 III, making a total (excluding the prototype) of 51 locomotives. These locomotives were developed for pulling heavy goods trains on the steep tracks of the Gotthardbahn from Lucerne to Chiasso, including the Gotthard Tunnel.

The electric motors available at the time were large and had to be body-mounted above the plane of the axles, but flexibility was required to negotiate the tight curves on the Alpine routes and tunnels. An articulated design, with two powered nose units bridged with a pivoting center section containing cabs and the heavy transformer, met both requirements and gave excellent visibility from driving cabs mounted safely away from any collision. The two motors in each nose unit were geared to a jackshaft between the drive axles farthest from the cab (SBB Ce 6/8 II) or farthest from the end (SBB Ce 6/8 III), with side rods carrying the power to the drivers. These locomotives, sometimes called the "Swiss Crocodile" or "SBB Crocodile", were highly successful and served until 1982.[3] The German model railway manufacturer Märklin published a book about their history in 1984.[4] Nine out of 51 total produced have survived, but only three are still in operation as preserved historical locomotives in Switzerland.[5]

Class Be 6/8Edit

Between 1942 and 1947, thirteen members of class Ce 6/8 II were upgraded with more powerful motors, to allow a higher top speed, and these became class Be 6/8 II. This required raising the jackshaft above the plane of the axles, necessitating a more complex system of side rods. In 1956, all eighteen members of class Ce 6/8 III were upgraded and became class Be 6/8 III.[6]

Narrow gaugeEdit

As well as standard gauge Crocodiles, there are also narrow gauge versions. The best known are the Rhaetian Railway (RhB)'s metre gauge locomotives of class Ge 6/6 I, the Rhaetian Crocodile. Several of these still run on passenger trains on special occasions. They are also used on freight trains in busy periods. The Bernina Railway (later merged with the RhB) also built a single Crocodile type, the Ge 4/4, nicknamed the "Bernina Crocodile". This locomotive survives and is being restored to operating condition.

Two other Swiss narrow-gauge railways also have locomotives nicknamed Crocodiles; the BVZ Zermatt-Bahn (BVZ) (which merged with the Furka Oberalp Bahn (FO) in 2003 to form the Matterhorn-Gotthard-Bahn) uses series HGe 4/4 I, known as the Zermatt crocodile, while the Chemin de Fer Yverdon-Ste. Croix owns a solitary class Ge 4/4 #21. Neither of these locomotive types have an articulated body, which leads some railfans to nickname them "false crocodiles".


Very similar locomotives were used in Austria as Austrian Federal Railways (Österreichische Bundesbahn) classes ÖBB 1089 and ÖBB 1189, and are often known as "Austrian Crocodiles".


The German classes E 93 and E 94, also used by the ÖBB as series 1020, are sometimes called "German crocodiles". They are sometimes nicknamed "Alligators", instead, because of their broader, shorter snouts.


The French SNCF 25 kV AC locomotives of classes CC 14000 and CC 14100, used mainly for iron ore trains on the Valenciennes-Thionville line [fr], have sometimes been called "crocodiles", although more commonly "flatirons". They are different from the Swiss crocodiles in that they are not articulated, but are a single long steeplecab or 'monocabine' with a bogie beneath each end.


Crocodile locomotives were also used in India. These locomotives, of series WCG-1, were used from 1928 between Bombay and Pune, and were all built to the Indian broad gauge of 5 ft 6 in (1676 mm). The first 10 locomotives were built by Swiss Locomotive and Machine Works. Vulcan Foundry of Great Britain constructed a further 31 examples for this line.[7][8]

Other Crocodile-like locomotivesEdit

Škoda-built narrow-gauge ChS11 locomotive at Bakuriani, Georgia

The articulated-body design was not unique to the Crocodiles. It was used in the United States on the Milwaukee Road class EP-2 "Bi-Polars", for example.

Many more locomotives adopted the design of long noses without articulation of the body. The single GE 4/4 of the Yverdon–Ste-Croix railway was known as the "Crocodile", despite being an elongated Bo-Bo steeplecab with articulated bogies beneath, rather than an articulated locomotive. This extended to painting it with large crocodile heads on each side.

In the United Kingdom, the LNER Class ES1 featured a crocodile-like design and was built between 1902 and 1904, both locomotives remaining in service until 1966, when No.2 was scrapped and No. 1 (BR No.26500) was preserved, now on display at Shildon Locomotion Museum.

The Panama Canal uses double-ended locomotives, known as 'mules', to act as land-based tugs to steer ships through the Canal's lock chambers.

Furthermore, some examples of locomotives similar in design to the Crocodiles, which were manufactured by Škoda can be found on the route between Borjomi and Bakuriani in Georgia.


  1. ^ "SWISS Ce 6". Archived from the original on 2013-02-16. Retrieved 2013-03-19.
  2. ^ This locomotive was later moved Zürich.
  3. ^
  4. ^ Stammer, H. S. "Märklin Krokodil." (Gebr. Märklin & Cie., 1984).
  5. ^ NZZ 2020, as above
  6. ^ "SWISS Ce 6". Archived from the original on 2013-02-16. Retrieved 2013-03-19.
  7. ^ "[IRFCA] Indian Railways FAQ: Locomotives - Specific classes : DC & Dual Current Electric". Retrieved 2013-03-19.
  8. ^

External linksEdit