In the mid 1950's, Lehigh Valley sent a few aging EMC NW1's to EMD for rebuild core units. One of the NW1's originally built in 1938, emerged in 1957 as a 600hp SW900M LV 130. The deal was set up at that time as a unit per unit trade in and units may have been 80-90% new after rebuilding. So, it's debatable whether or not it is a rebuilt NW1 from 1938 or a new SW900M from 1957 with some reused parts. Either way, from LV it would go to Conrail and be renumbered 8657 before ending up in west Texas as PVS 9. The 3926 numbering showed up later on the PVS and is some what of a mystery.