High Level. Rockhill Trolley Museum’s San Diego MTS 1019 (Siemens–Duewag U2) passed the Pop-Up Metro high level platform at the Rockhill Trolley Museum on the afternoon Saturday, October 9, 2021. Based on the original U2 design from cars that operated in Frankfort, Germany, this car served over 30 years in San Diego, California before retirement. Many of its class were purchased by Mendoza, Argentina and still operate in daily service.