predecessors. However, deferred maintenance and design defects have taken their toll on them. Muni has expanded its fleet with new Siemens light rail vehicles; the 151 Bredas will be replaced one-for-one starting in 2021. The first phase of 68 Siemens S200 LRV4s (for fleet expansion: 24 Central Subway + 40 Option 1 + 4 Phase W) were delivered between 2017 and 2019, ahead of the scheduled opening of the Central Subway. SFMTA's initial contract with Siemens called for a maximum of 260 cars to be delivered: 175 in the base order (151 of which are to replace the Bredas, and 24 for fleet expansion to accommodate anticipated ridership via the Central Subway), 40 as Option 1, and 45 as Option 2. Four more Siemens LRV4s were ordered in June 2017 for Phase W, which anticipates expanded service to Chase Center, using the Mission Bay Transportation Improvement Fund. Option 1 (+40) was exercised in 2015 and Option 2 was partially exercised (+30) in 2021 so there are firm orders for 249 LRV4s. The first LRV4 went into revenue service on November 17, 2017. Inactive/retired light rail vehicles The US Standard Light Rail Vehicle was an attempt at a standardized light rail vehicle (LRV) promoted by the United States Urban Mass Transit Administration (UMTA) and built by Boeing Vertol in the 1970s. Part of a series of defense conversion projects in the waning days of the Vietnam War, the LRV was seen as both a replacement for older PCC streetcars in many cities and as a catalyst for new cities to construct light rail systems. The USSLRV was marketed as the Boeing LRV and is usually referred to as such. The USSLRV was purchased by both Muni and the MBTA (Boston), but no other public transportation system in the United States purchased USSLRVs. Under the settlement terms of a lawsuit between Boeing Vertol and MBTA, MBTA was granted the right to reject the last 40 cars. The completed MBTA cars sat in storage until Muni purchased 31 of them. After the last LRV1 was retired in 2001, Muni stored two cars (1264 and 1320) at the Cameron Beach Yard (formerly the Geneva Streetcar Yard) for potential restoration and preservation by the Market Street Railway, but they declined to do so and both were scrapped in April 2016. Two LRV1s are preserved in museums: 1213 (since 2000), at the Oregon Electric Railway Museum