Also see our posting yesterday - Sperry Primer #1.
These are a few cars that are no longer with us having been sold, wrecked or rebuilt.
SRS X-107 at Danbury, CT test vehicle for new systems...sold to group in NY State 
SRS 140 at Jim Thorpe, PA new construction using R-12 carbody (Wrecked in Australia)
SRS 147-1 built 6-1976 new construction. Rebuilt to car 200 and in use in Europe
SRS 200 ex SRS 147