Starting in the 1920s, tens of thousands of X29 boxcars were built for the Pennsylvania Railroad, making the type as the first steel boxcar to be used in large numbers. Built and then rebuilt in a variety of configurations, X29s were common sights for decades, and MOW examples were active right up through the last years of Conrail, often still in the PRR yellow maintenance car scheme. I often saw (but never photographed) examples of these at Sewickley, PA.
PRR 2136, seen here preserved at the Railroaders' Memorial Museum at Altoona, PA.
X29 at Strasburg, boarded up pre-restoration
