SD/GP40 and DDA40X Prime Movers

[VGN Jess]

That's as good a speculation as there probably is. Thanks very much.

[beaulieu]

Things, people, abd times change. When the Union Pacific ordered the Centennials

David Neuhart was the Chief Mechanical Officer at Union Pacific, he was the deputy under Otto Jabelmann as CMO, the man responsible for the later Challenger, Northern, and Big Boy locomotives. When Jabelmann retired Neuhart succeeded him. Neuhart was responsible for the specifications and the ordering of all of UP's Gas Turbine and double engine Diesel locomotives. He was the last man to hold the office who had been involved in the design and specification of locomotives built to meet UP's particular needs. When Neuhart retired and was succeeded by Frank Accord as CMO times had changed and the era of hot 79mph Intermodal trains was nearing its end. Yes they lingered on long enough for UP to order the "Fast Forties" but then the "Arab Oil Crisis" hit and the price of fuel skyrocket, and the era of runthrough freights began and no other railroad wanted them in interchange. The Missouri Pacific accquisition was the final nail in the coffin as the Centennials were a west of Cheyenne only locomotive. A few of the Centennials had one last hurrah in the mid -eighties. Eventually the rise of 286k freight cars did allow the one Centennial to spread it's wings.

In the end the it's weaknesses outweighed its advantages. It had non-standard (to a GP/SD40) Turbocharger, Alternator, Traction Motors, and of course the Trucks. It's weight and the four-axle trucks limited the locomotives to operation west of Cheyenne, WY where the Challengers, Big Boys, and "Big Blow" Gas Turbines operated. When a diesel engine, alternator, or turbocharger failed it became a slippery D - 4 or 4 - D locomotive as each diesel/alternator combination powered only one truck. The reason for the non-standard Alternator and Traction Motors is because the Electrical System did not make trasition from Series-parallel to Parallel as speed increased like other locomotives did at the time. it was in full parallel right from the start which meant the Alternator had to be capable of higher amp output at starting and low speeds. The locomotives received a reliability upgrade beginning in 1975 and again beginning in 1979. Except for the two wrecked and retired, most Centennials had achieved 800k miles by 1980.

 

[SSW9389]

beaulieu

 

 Except for the two wrecked and retired, most Centennials had achieved 800k miles by 1980.

 

Don Strack has different mileage figures for the Centennials. He states that the class averaged a million miles each within five years. And some reached 2.2 million miles by the end of their service. See https://utahrails.net/articles/up-dda40x.php 

[SSW9389]

VGN Jess

That's as good a speculation as there probably is. Thanks very much.

 

 

There's actually some documentation if you look for it. Extra 2200 South's Associate Editor Dick Will wrote about EMD's new line in the January/February 1971 Annual Motive Power Review. Will wrote, "The so-called "new" EMD line will be delayed. Never planned to be as complete a change as the 40-line of 1965, it will probably make its appearance  in 1972, coincident with EMD's 50th Anniversary. Several factors have affected this seeming change. Current models are selling well, especially the lower horsepower ones. The horsepower race has slowed and rail technilogical break throughs such as the AC traction motor are not ready. Straight electric locomotives for various reasons, including pollution, are around the corner, at least before 1980. The new line, when it comes, may have little or no increase in horsepower and the changes so minor that no new numbers, such as GP50 or SD55, etc., will be used."

 

It would appear that Will had some direct knowledge from someone inside EMD.

 

Ed in Kentucky 

[beaulieu]

Here is a good look at a Centennial by a diesel mechanic who worked on them. His subject is #6922 which is preserved in a park in North Platte, NE.

Centennial video

[Paul of Covington]

   Thanks, beaulieu.   I saw about the first 30 minutes of it and will watch the rest later.   Fascinating.

[YoHo1975]

EMD also produced a 645E3B and E3C model before moving to the F block. And both had some use but not wide spread. I think it's safe to say that they were experimenting with the 950RPM 645 platform and just didn't ever get enough takers for it or it wasn't sufficiently reliable.

[beaulieu]

The EMD 16V-645E3B became the standard for virtually all GP/SD40 and their -2 variants. It is what people are refering to when mentioning the "Heavy Block". Look at when the rairoads are selling old SD40-2s and among the selling points, having a "Heavy Block" will be mentioned if the locomotive has one. Older locomotives were frequently upgraded with the reinforced block and old 16V-645E3 engines would be upgraded when they were used as cores for Unit Exchange completely rebuilt engines.

The 16V-645E3C diesel engine is a rarer version. It was an interim step towards the 16V-645F3 engine. It was used in F40 models rated at 3200 or 3300 horsepower. It was also used in the SD40-2SS models, though in UP's case they did not raise the rated horspower. BN also experimented with replacing the E3B engine with the E3C version in a small number of their coal service SD40-2 and rating them at 3300 hp.  These locomotives were given red background number boards to distinguish them. These locomotives should not be confused with BN locomotives which received yellow or blue background numbers as part of Oil tests so that if the locomotives needed oil added, the correct brand of oil would be used. IIRC the yellow numbers indicated Shell "Rotella T" oil, while the blue indicated the control group using BN's regular brand of oil, but the locomotives were used together for the duration of the test. BN also uprated a small number of C30-7s to 3300 hp. Eventually both the EMD and GE locomotives were returned to their original horsepower ratings.