In the early 1960s, Union Pacific started asking for a 15,000 hp (11,200 kW) 3-unit locomotive set to not only replace their turbine locomotives, but to bring a new generation of diesel locomotives to their rails, and then put them into use. The EMD (Electro Motive Division of General Motors) DD35 was a cabless booster (B unit) locomotive that consisted of two GP35 locomotives prime movers (engines) and electrical systems, mounted on a common frame and covered with a single cowling, riding on a pair of 4-axle Flexicoil trucks, so each prime mover was powering a single set of 4 axles instead of two sets of 2 axles, as in the GP35. Being a "B-unit", the DD35 lacked any sort of cab, and could only be run on the main line when connected with another "A-unit" to control it; the DDA35 is an "A-unit" version of this locomotive built in 1965. The 4-axle truck was considered too harsh on the trackwork to be in the lead, and thus EMD's response to UP's request was a 4-unit (instead of the requested 3-unit set) locomotive set, consisting of a pair of 2,500 hp GP35s sandwiching a pair of DD35s, to make one 15,000 hp locomotive set (basically six GP35s in four units)
EMD produced a demonstrator set like this in September 1963, painted in red and white (similar to the Frisco's livery). It was demonstrated on several railroads, but the only interest came from Union Pacific and Southern Pacific. UP bought the entire 4-unit demonstrator set, and followed with an order for 25 more, which were delivered from May through September 1964. The two demonstrator locomotives were numbered 72B and 73B; the 25 production locomotives were assigned 74B through 98B.
Southern Pacific ordered a small, three-unit sample, which were shipped with old-style bearings from six F3B trade-in units, but ordered no more. They were numbered 8400-8402, later 9500-9502, and still later 9900-9902. They were used on the SP's Sunset Route early in their lives, but were among the first locomotives sidelined whenever there was a downturn in traffic. Later, they were relegated to transfer service between West Colton and yards closer to Los Angeles, mainly Taylor Yard north of downtown. SP scrapped all three units in 1978 after their leases ran out.
The DD35s were initially quite unreliable; some of this was blamed on sand from the internal sandboxes getting in electrical gear, so new sandboxes were fitted on the walkways in 1969. They were among the last EMD road units to be built with DC generators and old-fashioned switchgear, which were more maintenance-intensive than the later AC/DC equipment.
Once teething troubles had been surmounted, the DD35s were reasonably successful, but they were less flexible than smaller units and thus all of the original B units were withdrawn by 1977 as the railroads fell on harder times. The DDA35s survived until 1981. All were eventually scrapped.
dd35, this, article, includes, list, general, references, lacks, sufficient, corresponding, inline, citations, please, help, improve, this, article, introducing, more, precise, citations, july, 2016, learn, when, remove, this, template, message, horsepower, di. This article includes a list of general references but it lacks sufficient corresponding inline citations Please help to improve this article by introducing more precise citations July 2016 Learn how and when to remove this template message The EMD DD35 was a 5 000 horsepower 3 700 kW diesel electric locomotive of D D wheel arrangement built by General Motors Electro Motive Division for the Union Pacific Railroad and Southern Pacific Railroad EMD DD35Two Union Pacific Railroad EMD DD35s sandwiched between a lead SD45 3638 and an unidentified trailing unit Type and originPower typeDiesel electricBuilderGeneral Motors Electro Motive Division EMD ModelDD35Build date1963 1964Total produced30SpecificationsConfiguration AARD D UICDo Do Gauge4 ft 8 1 2 in 1 435 mm Prime moverDual EMD 16 567D3AEngine type2 stroke dieselAspirationTurbochargedGeneratorDC generatorTraction motorsDC traction motorsCylinder size8 1 2 in 10 in 216 mm 254 mm Transmissiondiesel electricLoco brakeStraight air DynamicTrain brakesAirPerformance figuresPower output5 000 horsepower 3 730 kW CareerLocaleNorth AmericaRetired1981DispositionAll scrapped Contents 1 History 2 Original Buyers 3 See also 4 ReferencesHistory editIn the early 1960s Union Pacific started asking for a 15 000 hp 11 200 kW 3 unit locomotive set to not only replace their turbine locomotives but to bring a new generation of diesel locomotives to their rails and then put them into use The EMD Electro Motive Division of General Motors DD35 was a cabless booster B unit locomotive that consisted of two GP35 locomotives prime movers engines and electrical systems mounted on a common frame and covered with a single cowling riding on a pair of 4 axle Flexicoil trucks so each prime mover was powering a single set of 4 axles instead of two sets of 2 axles as in the GP35 Being a B unit the DD35 lacked any sort of cab and could only be run on the main line when connected with another A unit to control it the DDA35 is an A unit version of this locomotive built in 1965 The 4 axle truck was considered too harsh on the trackwork to be in the lead and thus EMD s response to UP s request was a 4 unit instead of the requested 3 unit set locomotive set consisting of a pair of 2 500 hp GP35s sandwiching a pair of DD35s to make one 15 000 hp locomotive set basically six GP35s in four units EMD produced a demonstrator set like this in September 1963 painted in red and white similar to the Frisco s livery It was demonstrated on several railroads but the only interest came from Union Pacific and Southern Pacific UP bought the entire 4 unit demonstrator set and followed with an order for 25 more which were delivered from May through September 1964 The two demonstrator locomotives were numbered 72B and 73B the 25 production locomotives were assigned 74B through 98B Southern Pacific ordered a small three unit sample which were shipped with old style bearings from six F3B trade in units but ordered no more They were numbered 8400 8402 later 9500 9502 and still later 9900 9902 They were used on the SP s Sunset Route early in their lives but were among the first locomotives sidelined whenever there was a downturn in traffic Later they were relegated to transfer service between West Colton and yards closer to Los Angeles mainly Taylor Yard north of downtown SP scrapped all three units in 1978 after their leases ran out The DD35s were initially quite unreliable some of this was blamed on sand from the internal sandboxes getting in electrical gear so new sandboxes were fitted on the walkways in 1969 They were among the last EMD road units to be built with DC generators and old fashioned switchgear which were more maintenance intensive than the later AC DC equipment Once teething troubles had been surmounted the DD35s were reasonably successful but they were less flexible than smaller units and thus all of the original B units were withdrawn by 1977 as the railroads fell on harder times The DDA35s survived until 1981 All were eventually scrapped Original Buyers editOwner Quantity Numbers NotesSouthern Pacific Railroad 3 8400 8402Union Pacific Railroad 27 72B 98B 72B and 73B ex EMD demonstrators 5653 and 5655See also editEMD DD35A EMD DDA40X EMD DDM45 ALCO Century 855 GE U50CReferences editPinkepank Jerry A 1973 The Second Diesel Spotter s Guide Kalmbach Publishing Co Milwaukee WI ISBN 0 89024 026 4 Barris Wes Union Pacific Centennials SteamLocomotive com Retrieved January 11 2005 Strack Don December 8 2007 Union Pacific s DD35 Double Diesels Utah Rails Retrieved from https en wikipedia org w index php title EMD DD35 amp oldid 1189980489, wikipedia, wiki, book, books, library,
