Alco S6 Builder List and Phases

S6 Roster Index

Ferrocarril del Pacifico Alco S6 702 in a builder photo at Schenectady, New York, June, 1955. Photographer: Alco.
Ferrocarril del Pacifico Alco S6 702 in a builder photo at Schenectady, New York, June, 1955. Photographer: Alco.
YearMonthRailroadOrder NoBldr NoPhaseQty
1955MayNorthern Pacific 750S323080922I1
1955MaySouthern Pacific 1033-1039S323080923-80929I7
1955MaySouthern Pacific 1040-1042S324281290-81292I3
1955JuneSouthern Pacific 1043-1051S324281293-81301I9
1955JuneFerrocarril del Pacifico 701-704S324281302-81305I4
1955AugustFerrocarril del Pacifico 705-708S324281306-81309I4
1955SeptemberFerrocarril del Pacifico 709S324981384I1
1955SeptemberFerrocarril del Pacifico 710-712S324981405-81407I3
1955OctoberFerrocarril del Pacifico 713S324981408I1
1955OcotoberFerrocarril del Pacifico 724S324981409I1
1955OctoberFerrocarril del Pacifico 714-717S324981410-81413I4
1955NovemberFerrocarril del Pacifico 718-723S324981414-81419I6
1955NovemberSouth Buffalo 40S324981420I1
1955NovemberSouthern Pacific 4634-4637S324981421-81424I4
1955DecemberSouthern Pacific 4638-4645S324981425-81432I8
1955DecemberSouthern Pacific 1052S324981433I1
1956JanuaryChihuahua al Pacifico 60S325581715I1
1956JanuaryNacionales de Mexico 5300S325581716I1
1956JanuaryOhio RiverTerminal Co. 56S325581717I1
1956JanuarySemet-Solvay 110S325581718I1
1956FebruaryArmco Steel 1202S325581720I1
1956FebruaryB. Perini & Sons 101S325581721I1
1956MarchWestern Maryland 151-152S325581722-81723I2
1956AprilSouth Buffalo 41:2S325581719I1
1956JuneSouthern Pacific 1053-1060S325581724-81731I8
1956JulySouthern Pacific 1061-1063S325581732-81734I3
1956AugustSouthern Pacific 1064-1069S325581805-81810I6
1956SeptemberSouthern Pacific 1070-1072S325581811-81813I3
1956OctoberSCOP 7133-1, 7133-2S326281814-81815I2
1956OctoberUS Pipe & Foundry 38S326281816I2
1956NovemberSouthern Pacific 1073-1078S326281819-81824I6
1956NovemberSouthern Pacific 1079-1083S326282281-82285I4
1956DecemberSouthern Pacific 1084-1090S326282286-82292I7
1956NovemberSouth Buffalo 42-43S327882293-82294I2
1956DecemberSouth Buffalo 44S327882295I1
1957JanuarySouth Buffalo 45S327882296I1
1957FebruaryBelt Railway of Chicago 420S327882297I1
1957JuneUpper Marion & Plymouth 61S327882298I1
1957JuneSloss-Sheffield Steel & Iron 15-16S327882299-82300I2
1957JulyRepublic Steel 317-318S328182301-82302I2
1957SeptemberColumbia Geneva Steel 1S328182303I1
1957SeptemberTennessee Copper 107S328182304I1
1958DecemberFundidora de Hierro y Acero 1S328182305I1
1959JanuaryFundidora de Hierro y Acero 2S328182306I1
1959OctoberRepublic Steel 153S328182307I1
1960NovemberUnidos de Yucatan 301S333683811I1
1960NovemberSCOP 7133-3S333683812I1
1960DecemberFundidora de Hierro y Acero 3S328182308I1


  • Larry E White and Dick Will, “Alco S5/S6/T6,” Extra 2200 South, April/May, 1970, pg 26-27
  • Joseph A. Strapac, Southern Pacific Diesel Locomotive Compendium, Vol. 1: Pre-1965 SP Numbers, T&NO and Cotton Belt Subsidiary Roads, Shade Tree Books, 2004, pgs 26-28, 49
  • Joseph A. Strapac, Southern Pacific Diesel Locomotive Compendium, Vol. 2: Post-1965 SP and Cotton Belt Numbers, Union Pacific Transition, Shade Tree Books, 2007, pgs 32-36
  • John R. Signor and John A. Kirchner, The Southern Pacific of Mexico and the West Coast Route, Golden West Books, 1987
  • Russell Wilcox and Dick Will, “Western Maryland,” Extra 2200 South, January/February, 1973, pg 17