Acumulador de Carga Rápida

Acumulador de Carga Rápida (ACR) (transl. fast-charging battery) is an electric tram system powered by onboard supercapacitors marketed by Spanish manufacturer Construcciones y Auxiliar de Ferrocarriles (CAF). Trams equipped with ACR are fast-charged while at stops; elsewhere they require no overhead line, which is desirable for reasons of safety, reliability, cost, and aesthetics.