It is practically a lesser-known version of the DDA40X; having lower horsepower, and less features (such, being the early "wide-cab" which was featured on such).
None are preserved.
The Union Pacific and Southern Pacific were the only railroads to purchase the DD35; and like the DDA40X, they were one of the only eight-axle ("D-D") diesel locomotives to be produced by EMD, and some of the only eight-axle diesel locomotives to operate in North America. They, however, weren't as successful as the DDA40X, and often suffered the same problems and issues as the GP35; it's compatible, four-axle counter-part. They had awful "teething-troubles", (like with the BR Class 17 'Clayton') to whom the engine(s) wouldn't function properly, their brakes often failed, and often had one or both of the engines shut down due to overheating (although one engine failing would result in the entire locomotive itself to completely fail unexpectedly, furthermore resulting in a long-term overhaul).
Most "cabbed" DD35 units on the Union Pacific were all retired quicker than the GE U50C (including its counter-part); which such type of GE wasn't very fuel-efficient or reliable after only a few months to a year in service. Yet, some remained in service much longer until around
The "cabless" DD35 "booster" originally was produced before the DD35A units were built.
The SP had only three DD35 units all which were renumbered numerous times and were scrapped one-by-one from 1973 to 1978.
The original DD35 unit ordered by the SP before the other two retained such designation, while the two later DD35 units were often known as "A-units" to help distinguish the original from the latter, although the "A" designation (obviously) is used for "cabbed" units.
The DD35 was essentially 2 GP35 units on a single frame.
An EMD demonstrator consist (during 1963) was compiled of a DD35 sandwiched between 2 GP35's, which was used to demonstrate a form of "combined power" similar to what the EMD FT and other F units (besides subsequent E units) were originally built for; being compatable and able to operate together without having to have a specific locomotive attached to one another, and have every locomotive in a consist operate from the engineer controlling the lead locomotive. This technique eventually developed the "distributed power unit" (DPU) form of having multiple locomotives operate on different parts of the same train (from front, to middle, and/or rear) and be controlled by the engineer of a lead locomotive simultaneously.
"DD" indicates the use of EMDs "D" eight-axle trucks; besides being a designation for "Double-Diesel".
Some narrow-gauge foreign diesel locomotives use DD35 parts, and some are even rebuilt from a DD35.
Southern Pacific's only DD35 unit (at the time of the type's introduction; though, ordered before the other two) was originally the prototype and demonstrator unit which was often paired with GP35 units because of how the DD35 was originally used as a form of "combined power" for the EMD GP35 and other four-axled diesel locomotives.
The lone SP DD35 unit (scrapped long after the other two) remained on one of the SP's Colton Yard's "deadlines" from 1973 to 1978, and was ultimately scrapped in 1979.