 There were four different models of trailer available.They were made by Gräf & Stift (type OA I), Kässbohrer (without model designation), Lohner (type OM 5/1) and Schumann (without model designation).The oldest vehicles in the current fleet are the 23 high-floor Gräf & Stift articulated trolleybuses built between 1988 and 1994.