@lina FYI Konstals are using more or less the same tech as Americans' PCC, which is super old; pre-war there were plans to loicence it from them but post-war the design was reverse engineered and directly copied from inspired by units graciously handed over by the Czechoslovaks with liberal use of political pressure and threats, who held an actual loicence. They were modernised a few times but fundamentally they're still the same.