ADtranz low floor tram

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.

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.

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