Interesting photo. What's the reason this trolleybus was in Budapest?

816 and 820 was tested in Budapest in summer of 2007, at that time the whole retired fleet of Neoplan N6121s of Lausanne was for sale. Note that they were retired in 2005, after just couple of years of service, due to maintenance and operational concerns. The test results in Budapest weren't promising either and it took other couple of years to find their way to Ploiesti.