SSB DT 8

The DT 8, also known as S-DT 8, is a type of light rail vehicle used on the Stuttgart Stadtbahn system, produced in multiple iterations by various manufacturers, including Duewag and Stadler, since 1985.

Technical specifications
The trains are formed as two-car sets, with steel car bodies. Up to three sets can operate in multiple.

First generation: DT8.4 & DT8.S
Testing of three prototype trains began in 1982 on the Alb Valley Railway.

Additional batches of Duewag-built DT8 cars were delivered in 1998, 1989–1990, 1992, 1993, and 1996; these were initially designated DT8.5, DT8.6, DT8.7, DT8.8, and DT8.9, respectively. These variants were all largely identical, aside from the removal of retractable steps from the DT8.6 onward.

From 2007 to 2017, the DT8.5, DT8.6, DT8.7, DT8.8, and DT8.9 cars were thoroughly refurbished by Bombardier. The motors on each were replaced with AC motors, and the interiors were redesigned to resemble those of the DT8.10 and DT8.11. Following the refurbishment, all five batches were renumbered (from 3087–3234 to 4087–4234), and officially redesignated as the DT8.S.

Second generation: DT8.10 & DT8.11
The second generation of the DT8, dubbed the DT8.10, was built jointly by ADtranz and Siemens. 24 units were ordered, with deliveries beginning in April 1999. Visually, they are largely identical to their predecessors, inside and out, though they include a number of improvements, such as the addition of IGBT inverters and AC motors, open gangways, LCD information displays, and air conditioning.

Later, an additional 27 units, designated DT8.11, were ordered from Bombardier. Delivered from 2004 to 2005, they are almost completely identical to the prior DT8.10s.

Third generation: DT8.12 – DT8.15
Built by Stadler Rail, the third-generation DT8 is based on the company's Tango model. Its exterior design differs greatly from prior DT8 variants, with a streamlined, aerodynamic front fascia, though its interior is similar to that of its predecessors. Like the second-generation units, the third-generation DT8 has AC motors, air conditioning, and open gangways between cars. They are equipped with sliding plug doors, a departure from the swinging doors of earlier variants.

The first twenty, designated DT8.12, were ordered in 2010. 20 additional sets (DT8.14) were ordered in 2014, followed by twenty more (DT8.15) in 2017. 30 units, tentatively called DT8.16, are currently on order for delivery beginning in 2025; they are intended to replace the remaining original DT8.4 units.

Preserved examples
Two prototype cars were formerly stored at Heslach depot, and were to be moved to the Straßenbahnwelt Bad Cannstatt in 2018.