page_title: ALCO DL-109
section_title: History
hierarchical_section_title: ALCO DL-109 / History
context_page_description: The ALCO DL-109 was one of six models of A1A-A1A Diesel locomotives built to haul passenger trains by the American Locomotive Company between December, 1939 and April, 1945. They were of a cab unit design, and both cab-equipped lead A units DL-103b, DL-105, DL-107, DL-109 and cabless booster B units DL-108, DL-110 models were built. The units were styled by noted industrial designer Otto Kuhler, who incorporated into his characteristic cab the trademark three-piece windshield design. A total of 74 cab units and four cabless booster units were built.
context_section_description: All models developed 2,000 hp (1,490 kW). The first unit built as ALCO Specification DL-103b was 4 ft 5 in (1.35 m) longer than the other cab units, and became Chicago, Rock Island and Pacific Railroad #624. The DL-103b had the two radiator sections positioned together at the end of the carbody, while all other units had a split radiator arrangement with one placed at the back of the unit and one situated in the middle. The DL-103b was built with twin 6-cylinder ALCO 538T diesel engines as prime movers; all other DLs in this series were built with the newer twin 6-cylinder ALCO 539T diesel engines. The DL-103b also had all-electric driven accessories, while the later models had belt-driven accessories.  The differences between all subsequent models were minor.  The DL-105s went to the Rock Island as #622 and GM&O #270-271. All other early customers got DL-107 cab units and DL-108 boosters until the first DL-109 was delivered to the New Haven.  During the war, the Gulf, Mobile & Ohio and Southern Railway bought DL109s and the Southern bought the only DL-110.  It is not known whether this is because the model was a significant improvement, was the model approved for wartime production, or both.
  The New York, New Haven and Hartford Railroad received special permission from the War Production Board to purchase #0710–#0759 as dual-use (passenger/freight) locomotives; they were built between 1942 and 1945.  Passenger-only locomotives (including the rival EMD E6) were not approved for production until early 1945.  The first 10, #0700–#0709, were delivered starting right after the attack on Pearl Harbor in December 1941 from ALCO's Schenectady factory, allowing the road to prove their freight-hauling abilities just in time. The New Haven owned the most DL-109s, rostering 60 units (of the 62 built) in 1945. The New Haven DL-109s could be found hauling passenger trains during the day and freight trains at night.
  There were different classes among the New Haven units noting some differences between the manufacture of each batch. Initially, they were simply listed in two groups in the Summary of Equipment, with #0700–#0709 listed separately (with a different weight and tractive effort) than the remaining DL-109 locomotives. The 9-30-1945 Summary of Equipment designates four different classes: DER-1 (Diesel-Electric Road) units #0700–#0709 had the original design with a mass of vents on the roof, DER-1b (#0710–#0719) were nearly identical, with square winterization hatches over the roof fan housings (which were also applied to the original units following the winter of 1941), DER-1b (#0720–#0729) and DER-1c (#0730–#0759) all had simplified rooflines, and other minor variations in appearance. 
  The classes would remain the same until the start of an extensive rebuilding program. In the 6-30-1949 Summary of Equipment the class designations were adjusted into three classes: DER-1a (#0700–#0709), DER-1b (#0710–#0749) and DER-1c (#0750–#0759). The class was rebuilt from 1949 to 1951, replacing the plywood sides, removing the decorative side windows in favor of a steel screen, and several other changes, with only #0740 retaining its original appearance after being rebuilt.
  Two DL-109s received a special rebuild c1953 to make them able to "MU" (multiple unit) with more than one other unit; originally, they only had the MU cables on the rear, meaning that only a back-to-back pair could be made. The two special units had cables put on the front so they could be used to make a 3-unit set for longer trains.  One of the units had the nose rebuilt with an access door, raising the headlight and changing the contour of the nose.
  In the Winter of 1953 to 1954  New Haven A-A-A units #720-722 with #0721 in the lead could be seen in far northern Maine on the Bangor and Aroostook Railroad, helping haul massive tonnage of potatoes, usually in the now-famous red white and blue "State of Maine" products reefers. These were leased by The BAR.
  The DL-109s eventually ran their last miles in the late 1950s in local commuter service around Boston.  One special u
caption: Units #50 and #50A, the Santa Fe Railway's only DL locomotive set, lead the Super Chief during World War II.
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