Today we'll take a look at the history of the SD40-2, one of the most successful diesel-electric locomotives ever.
Electro-Motive Division (of General Motors) introduced the "Special Duty" series in 1951, with the first model of the series being the SD7, which debuted in May of that year.
The SD series would prove successful, and go through many updates throughout the decades, with the most recent model being the SD70ACe.
However, in 1972, what would prove, so far, to be the most successful in the series would debut - the SD40-2 (ess-dee fourty dash two). It would prove immensely popular, with several variations.
The SD40-2 is an update of the previous model, the SD40, with the -2 indicating updated electronics, especially modular electronic control systems.
They were equipped with EMD's 16-645E3 turbocharged V16, which produced 3,000hp and powered 2 three-axle trucks, a C-C arrangement. The normal specification units were 68' 10" in length, 15' 7 1/8" high, and 368,000lbs.
They were built by EMD in the U.S., GMD (General Motors Diesel) in Canada, as well as Material y Construcciones S.A. (MACOSA) and Equipmentos Villares S.A. (EVSA) for the South American market. A total of 3,982 would be built from introduction in January of 1972 until October of 1989, when the SD50 series replaced them.
They would end up scattered around the world, from across North America to Brazil, Guinea, and Mauritania.
Over the production run several variants and derivatives would appear; the SD40T-2 "Tunnel Motors" for Southern Pacific and Rio Grande, which had rearranged components to give better performance in long tunnels, namely the cooling system, which moved the air intakes from near the top of the body to just above the walkways, to allow access to cooler, cleaner air; the SD40-2W for Canadian National, which had the Canadian "Safety Cab"; BB40-2 for Ferrovia Central Antlantico in Brazil, which replaced the C-C trucks with 2 two-axle narrow gauge trucks under each end, of a B-B+B-B arrangement; "Snoots", which had extended short hoods to house radio control equipment; Norfolk & Western and Southern would order high short hoods, as was their practice; and the SD40-2F, for CN, which had a full width carbody and wide/safety cab.
And that's just the direct variants, so let's move to the derivatives: JT26CW-SS/British Rail Class 59; GT26CW-2 for Yugoslavia, South Korea, Iran, Morocco, Peru, and Pakistan; GT26CU-2 for Zimbabwe and Brazil; and the GT26HCW-2 for Algeria.
As you can tell, I wasn't kidding when I said they were popular and ended up all over!
Among the regular SD40-2, Burlington Northern would have the most, with 835 on the roster.
They would prove adept at any task, from fast intermodal to heavy coal trains, but would eventually be replaced on mainline duties by newer, often more powerful and more efficient power. EMD would directly replace them with their SD50 line... which would not be a worthy successor, and would lead to the EMD's loss of dominance in the locomotive market to GE.
A great many, probably most, SD40-2s are still in service today - Class 1 railroads still employ many, mainly in local or switching service, and they have also proven very popular on shortlines and regional roads.
There have also been several update and upgrade projects over the years, with some still ongoing, resulting in several new derivatives; the SD40N, SD40-3, SD22ECO, SD30ECO, ET23DCM.
Though the SD40-2 is still very much a daily performer on many railroads, their historical value has been recognized, and some have been preserved.
That's all for this little bit of locomotive history - thanks for reading!
Very useful locos and appreciate their longevity as they can be modified for specific situations like the air intake move for long tunnels