EMD DDA40X

The EMD DDA40X was a heavy diesel locomotive Union Pacific Railroad. Between June 1969 and September 1971 47 locomotives were built by General Motors Electro-Motive Division of La Grange, Illinois. They were given the numbers 6900-6946.

Design and technology

The locomotive was intended for use on heavy freight trains on the mountain ranges of the Union Pacific, which were previously dealt in part with up to eight -propelled multiple unit trains. In the summer of 1965, the Company had already had experiences with the DD35A collected, which consisted of two mounted on a frame GP35 locomotives basically. Now when decency the centenary of the First Transcontinental Railroad for 1969, the Board of Directors, to be constructed for this occasion a special locomotive decided. You should be the largest and most powerful diesel locomotive in the world.

The DDA40X based on the use of technical equipment of two GP40 locomotives in a single locomotive body, which propped up on two -axle bogies. The locomotive was equipped with a single cab at the end. It is driven by electric traction motors suspended eight, the electricity was produced (output 3345 hp) with flanged three-phase alternator by two 16 -cylinder diesel engines. The electricity generated was rectified by silicon diodes, this technique was applied to the DDA40 for the first time and later found, as well as many other innovations, moving into other diesel-electric locomotive series.

Operational use

The first locomotive was delivered in April 1969 to the Union Pacific, just in time for the anniversary celebrations, where she drew the special train " Golden Spike ". Delivery of the other 46 machines took place until September 1971. The machines were mostly used to 1980 before fast freight trains, with the decline in cargo volume early eighties they were taken out of active service and mothballed. In March 1984, 25 machines were reactivated as part of the growth of the American economy increased carrying capacity was needed. In late 1986 the machines were but then been permanently withdrawn from service.

Machines received

Of the original 47 locomotives 13 vehicles have been preserved to this day, mostly in railway museums. A machine ( 6936 ) is still in working order and is used by the Union Pacific Heritage Fleet for special trips.