Metro began testing a fleet of new hybrid diesel-electric buses in 2002, intending to use them in the bus tunnel before and after the conversion to joint bus-rail operations. The first few of a planned fleet of 235 hybrid diesel-electric articulated buses began operating on tunnel bus routes in June 2004. The Breda dual-mode trolleybuses were removed from the tunnel in January 2005 and would later be refurbished into electric-only trolleybuses for use on the city's trolleybus network. The last day of trolleybus operation in the tunnel was January 24, 2005, with only a single dual-mode bus in service on the final day.