| AT&SF SD26 4668 at Corwith Yard, Chicago, Illinois, September 1979, photo by Chuck Zeiler. Built in June 1960 as AT&SF SD24 968 (c/n 25878) on EMD Order 5617, it was renumbered to 4568, rebuilt to SD26 4668, retired by the AT&SF December 1986, sold to Springfield Terminal becoming ST 640. The Santa Fe SD24's were rebuilt at San Bernardino between January 1973-78, upgrading the locomotives to the then-current technologies. Included in the upgrade was replacement of the troublesome high voltage and transition circuitry with EMD's Dash 2 circuit cards, replacement of the 16-567D3 with a new 16-645D3 prime mover, which in turn boosted a unit's horsepower rating from 2,400 to 2,625, and installation of a central air intake and filtration system. The air intake modification created a hump on the roof behind the cab, forcing the air reservoir tanks (which had occupied that position) back along the roof. The as-built low short hood and one-piece windshield over the nose was retained, although in later years the one-piece windshield was changed to two-piece to have the same size and shape windshield glass across several classes of Santa Fe locomotives and simplify maintenance part stockpiles. The original SD24 blower bulge was replaced with a second generation blower housing. Some (but not all) received a cab roof air conditioner. |