[3] With around 70 trams in service, as of 2023, the largest operator of GT4 is CTP, the public transport company in Iași, Romania.

[4] The GT4 was developed because the longer six-axle articulated trams with Jacobs bogies, such as the GT6, were not suitable for the Stuttgart network, which had a large number of sharp curves and steep gradients due to the city's hilly topography.

The design of articulation is unique: both bogies are connected by an underframe, upon which the two halves of the tram body rest.

[2] The bi-directional variants have a second driver's cab and additional side doors, unlike the uni-directional models.

The car was initially used by Tosaden Kōtsū and since April 2014 has been operated on the Fukui Railway[8] as their type F10 tram under the nickname "Retram" (レトラム).