SBB Re 620

The Re 620, Re 6/6 in the old numbering scheme, are six-axle, electric locomotives of Swiss Federal Railways (SBB CFF FFS), which were acquired as a replacement for the Ae 6/6 for heavy services on the Gotthard Railway. They were produced between 1972 and 1980 and are the most modern of the so-called "Gotthard locomotives".

Construction and Technology

To reach the necessary tractive effort, a construction comprising six driven axles was necessary. In order to still get good running characteristics in curves, they were built into three two-axle bogies instead of two three-axle bogies as on the Ae 6/6. The middle bogie can move sideways, and the three bogies are connected by elastic cross couplings. Two of the four prototypes (11601, 11602) were built with a split locomotive body, whereby the joint may only move on an horizontal transverse axis to allow for changes in gradient, similar to the Rhaetian Railway Ge 6/6 ^II.

The other two prototypes (11603, 11604) got a softer secondary suspension instead of the joint, which proved to be so reliable in everyday use that all other locomotives of the series were built this way. Nevertheless, the two prototypes with a split body are still in regular operation. The exterior design is similar to the Re 4/4^II (Re 420), as are the driver's controls and the conventional transformer technology with fixed running notches, which was applied for the last time for this locomotive. In contrast to the Re 4/4^II, the Re 6/6 has two transformers (one power and one control transformer), which are mounted on the frame between the bogies. Due to the higher roof, the Re 6/6 looks more brawny than the Re 4/4^II, especially when seen from the front side.

Operations

The Re 6/6 is equipped with multiple unit train control together with Re 4/4^II, Re 4/4^III (Re 430), Re 4/4^IV and RBe 540. In passenger traffic they pull heavy passenger trains over the Gotthard route (as an alternative to a double heading of Re 4/4). In freight traffic they are used all over Switzerland for heavy trains, on the Gotthard route very often together with an Re 4/4^II or Re 4/4^III. Such a couple, often referred to as "Re 10/10" (both locomotives are Re class, so the couple is Re class; 10/10 means that they overall have 10 driven axles out of 10), is capable of pulling the maximum train weight of on 2.6% gradients of the Gotthard line. For heavier trains, up to 1600 tons are operationally feasible, an additional bank engine has to help push the train in order to not overload the couplers.

Locomotive 11638 was retired and scrapped in 1990 due to an accident. For the renumbering to the UIC-conforming new numbering scheme in 1992, only the still existing locomotives were considered, thus the 11638 did not get a new number. But the renumbering was never done consistently. During 2005, the UIC numbering scheme was reworked, and 620 001 (instead of 000) was defined to be the smallest number. To make things easy, the scrapped 11638 also got a new number, 620 038. About half a dozen locomotives bore the new numbers at the beginning of 2006.

After two locomotives were tentatively equipped with radio remote control for pushing trains on the Gotthard line (such that the locomotive pushing at the end of the train may be controlled by the engineer at the front), about 30 locomotives were equipped with it in 2000. To make them administratively distinguishable, they got the new designation Ref 6/6.

When SBB was divided into passenger services and freight, the first thirteen locomotives (11601–11613) remained in the passenger division. On 1 January 2003 they were exchanged against the Re 460, meaning that now all remaining 88 locomotives were assigned to SBB Cargo. Due to the reassignment of the Re 460 to the passenger division, the Re 6/6 again dominated freight traffic on the Gotthard line.

The locomotives are assigned to the workshops in Erstfeld, Bellinzona and Lausanne (Lausanne: 2000, today unknown). Revisions are done at the main workshop at Bellinzona.

Naming and numbering

Since the () Ae 6/6, naming of locomotives and EMUs (e.g., SBB RABDe 500, RABe 501) is common practice in Switzerland. Re 620 locomotives are numbered 11601–11689 and named after Swiss communes (except Bad Säckingen). In addition to the communes' names, also their coat of arms is indicated on the side of each engine.

The following table lists Re 620 locomotives with their number, commune names and respective coat of arms (COA). Crossed out numbers indicate scrapped locomotives.

Gallery

Image:Sbb 1643 - martigny - 20-07-1985.jpg, Re 6/6 11641 in its original condition leading a passenger train in the Rhône valley at Martigny.
File:SBB Re 6-6 Nr. 10601 Wolhusen - 20130217.jpg, SBB Re 6/6 Nr. 10601 Wolhusen (prototype with split body)
Image:SBB-Re-6-6-11611.jpg, side view of Re 6/6 11611 with air conditioning
Image:Front-Re11611.jpg, Front view of Re 6/6 11611 with air conditioning, UIC conforming plug, steps, headlights and red livery
Image:2012 08 02 02 Re 6 6 11602.JPG, The first two prototypes 11601 and 11602 were built with joints in the body
Image:2013 11 01 Re 6 6 11603 Waedenswil 1.JPG, The second two prototypes 11603 and 11604 were built without joints in the body
File:Airolo, SBB Re 6-6 with express train at the mouth of the Gotthard tunnel (Com LC1943-001-019).jpg, Express train in 1983
SBB CFF FFS Cargo Re 620 046-3 "Bussigny" in Wil SG.jpg, SBB Cargo Re 620 046-3 "Bussigny" in Wil

See also

* List of stock used by Swiss Federal Railways
* Swiss locomotive and railcar classification

References

* ''This article was mostly translated from the German language version of August 2006.''

{{Standard gauge locomotives of Switzerland

15 kV AC locomotives
Bo-Bo-Bo locomotives
Re 620
Electric locomotives of Switzerland
Standard-gauge locomotives of Switzerland
Railway locomotives introduced in 1972
Brown, Boveri & Cie locomotives
SLM locomotives