In December 2003, the TPG began road-testing a , double-articulated, mega-trolleybus manufactured by Hess and Vossloh Kiepe. The bus can carry 150 passengers. It entered passenger service in January 2004 on line 10 to the airport. This vehicle was created by adding a middle section to a trolleybus that was originally a single-articulated, vehicle. In 2005–06, TPG purchased ten all-new double-articulated trolleybuses from Hess, length , and they are numbered 781-790. As of late 2006, TPG's fleet included 92 trolleybuses, all articulated (of which eleven were double-articulated).