The "Beep" (also referred to as the SWBLW) is an individual switcher locomotive built in 1970 by the Atchison, Topeka and Santa Fe Railway at its Cleburne, Texas, workshops. Technically a rebuild, the Beep (a portmanteau of a B-B wheel arrangement and "Baldwin Geep", whose official designation was derived from "SWitcher, Baldwin Locomotive Works") originally entered service on the Santa Fe as a Baldwin Model VO-1000. Following its successful CF7 capital rebuilding program, the company hoped to determine if remanufacturing its aging, non-EMD end cab switchers by fitting them with new EMD prime movers was an economically viable proposition. The conversion procedure proved too costly and only the one unit was modified. In 2008-2009, this locomotive was retired and stored operational at Topeka, Kansas. In May 2009 the unit was donated to the Western America Railroad Museum in Barstow, California.