The ADtranz low floor tram was introduced in the 1990s as the world's first tram with a completely low floor. This tram was developed by MAN for the Bremen urban transport system. The prototype, tram number 3801, was first publicly introduced on 9 February 1990. From 1991 to 1993, it was tested in many European cities. Ten German cities have purchased this type. Adtranz took over the rail division of MAN in 1990.
The naming scheme is GTxN/M/S/K from German Gelenk-Triebwagen (articulated propelled railcar) with x axles for a specific gauge (Normalspur - standard gauge, Meterspur - meter gauge, Schmalspur - narrow gauge, Kapspur - cape gauge). Delivered models include the standard-gauge version that was named GT6N or GT8N and the metre-gauge version that was called GT6M.
ADtranz low floor trams come in lengths of three or four modules, all of which are approximately the same length. Under each module lies a bogie; the low floor, however, constrains the bogie's movement. Two of the axles are electrified linked to the bogie truck by means of a universal joint. Characteristic of this tram is its ability to follow curves, which requires a special track layout. This occurs when the first or last module drives through an arc and drags the other two modules (which are on the straight) after it.
ADtranz low floor tram Wikipedia
The company Hansa Waggonbau in Bremen had been among the first to introduce the concept of articulated railcars which was delivered to customers with the GT4 model since 1959. The fading interest in tram operation in the 1970s led to a bankruptcy of the company in 1975. Renewed interest in the concept sprang up in the late 1980s with Bremen and Munich to look for modernized versions of the GT type series. This included the wish for a low floor variant and all rail cars to be propelled. MAN took over the task to create a test model (number 561) in 1985 which had 3 units (instead of the 2 units of the GT4). The first model be on delivery (GT6N) was a three part electrical multiple unit (EMU) as well.
Tram operation includes:Augsburg: 12 GT6M
Frankfurt (Oder): 8 GT6M
Jena: 33 GT6M
Mainz: 16 GT6M
Zwickau: 12 GT6M
Berlin: 150 GT6N
Bremen: 78 GT8N
Munich: 70 GT6N
Norrköping: 4 GT6N (bought from Bremen and Munich)
Nuremberg: 14 GT6N
Kumamoto: 4 GT4N
Braunschweig: 12 GT6S
Takaoka: 4 GT4K
Okayama: 1 GT4K
Toyama: 7 GT4K
On the small tramnet in the Swedish city Norrköping they have four second-hand Adtranz-tram services since the end of the millennium. The different trams is the prototype "Bremen" (tram 3801) and three trams from Munich.
The response on the Adtranz's second generation trams was not successful on the market. Only Munich and Nuremberg ordered this type. Except for being renewed with the latest technology, it also featured a larger distance between the axles knows to this material (2 meters instead of 1.85 meter) so that the leg space on top of the bogies could be increased. Another difference is, which there here really talk is not of a 4-moduled tram (as the one provided to Bremen), but previously of two double-modulated trams. In the middle, the articulation has been lengthened and redesigned, so that the movements of the first and last two modules couldn't influence each other. Because of this swinging the modules is limited at - and driving out the arcs.
Tram operation includes:Munich: 20 GT8N
Nuremberg: 26 GT8N
When Bombardier Transportation bought Adtranz, it ceased production of the GTx-trams; however, the concept of articulated railcars for low floor trams was carried forward to its Incentro model, which was eventually replaced by Bombardier's standardized Flexity family of vehicles. Of these, the Flexity Berlin was specially designed with a layout similar to the Incentro and GTx-series and can be considered to be among its immediate successors. These trams entered revenue service in 2011.
Competing manufacturer Siemens Transportation Systems had been offering the Combino models with articulated railcars until some Combino construction flaws were observed. The new Avenio family of tram models features a double articulation join similar to the second generation of ADtranz low floor trams. These have already been sold to Budapest and Almada (Portugal).
Similar trams are also being manufactured by Alstom (Citadis), AnsaldoBreda (Sirio, and CAF (Urbos), among others.