• EMD "DD-series" official thread (covers all variations)

  • Discussion of Electro-Motive locomotive products and technology, past and present. Official web site can be found here: http://www.emdiesels.com/.
Discussion of Electro-Motive locomotive products and technology, past and present. Official web site can be found here: http://www.emdiesels.com/.

Moderator: GOLDEN-ARM

  by Phil Hom
 
This item is covered in the US Patent and Trademark office. It is US patent number 3,313,244 (granted 11 April 1964, filed May 15 1964)

While Alco and GE used span bolster in their dual high horsepower freight locomotive, EMD engineer Ludvil F. Koci designed this truck since the truck weights less than a dual B truck with its span bolster. In addition a span bolster raises the height of the locomotive which means a higher center of gravity.

The patent has two claims, both are very technical and not spelled out in layman terms. You can view this patent on the USPTO.gov web site once you download the TIFF reader on your computer or use another web site if the supprt patents before 1977.

  by DutchRailnut
 
Believe those are rear sand boxes

  by pennsy
 
Correct, those are sand reservoirs for delivering sand to the rails for traction enhancement.
  by NV290
 
More then likley, you will never see any reincarnation of the beasts, even modernized.

As has already been pointed out, the fact that building ONE loco to replace two can actually hurt you when you have an issue with one being in the shop or failing line of road.

The other is the traction issue. Traction now is the biggest limiting factor in locomotive pulling power. Building more powerful loco's HP wise is not an issue, getting that power to the rail is. I run AC6000's almost daily, and i get wheel slip almost daily. And that is with 6,000hp distributed over 6 wheels. The idea of trying to squeeze two 6,000hp engines in one frame and then putting each through a 4 axle truck would not work. I don't even thing you could do it with 4,000 hp per truck.

Wheel slip systems have made incredible advancements but there is only so far you can go. Radial trucks have helped as well not just in traction but also in track wear prevention. But the trucks have more moving parts and higher upkeep bills. The GE Radial trucks on our 6,000's have been problematic as they wear rapidly.

I highly doubt any railroad would want to buy a loco that is even an ultra modern version of a DD40. There are far too many cons vs pros.
  by Engineer Spike
 
First, the DD35 was 2 GP35s on one chassis, and the DD40 was 2 GP40s. These engines were meant for high speed operation. I don't think that this wold be possible for a unit designed for maximum TE. In spite of all the advances with AC traction and wheel slip systems, eventually we will reach the maximum power vs te. It is impossible of surpass the laws of physics.
Earlier posts have talked about the fact that a failure of one unit means more problems, the fewer units on the train. I'll give you an example. Where I work, we used to get 4 unit consists of SD40s. One time a pinion broke. We were able to set out the unit, along with about 25% of the tonnage. Now we have 2 AC units. If this happened now, we would have to leave half of the train, unless there was a spare unit to pick up.
  by splitrock323
 
DDA40X's were built in the pre Dash-2 era. But they had many dash-2 components. Which fans did they have for cooling? I want to kitbash my models with better looking fans and wondering if I should use late SD40/45 fans or early dash-2 types?

Any help or reference pictures woould help.

Thanks,

Thomas
  by SAR RX
 
Just wondering if anybody can tell me how many, if any DD40x's are still in existance or preservation? I'm down here in Australia and finding info on these locos is a bit difficult. I'll try Wiki, but I'm not always sure whether the information on there is up to date.
Thanks.
  by Allen Hazen
 
SAR RX--
I think the DD-35 were all scrapped. Union Pacific has kept one DD-ao "Centennial," which they use on special trains. I think at least one other Centennial has been preserved for static display: possibly at the California State Railroad Museum in Portola.
.... Wasn't Australia in danger of getting its own double diesels at one stage? I seem to remember that one proposal a decade or so back-- not sure whether it was a bid for the NSW request that led to the 82 and 90 class or for the National Rail request that led to the NR class-- was from Morrison-Knudsen, who wanted to build a locomotive powered by two 12-645 engines.
  by Jtgshu
 
SAR RX wrote:Just wondering if anybody can tell me how many, if any DD40x's are still in existance or preservation? I'm down here in Australia and finding info on these locos is a bit difficult. I'll try Wiki, but I'm not always sure whether the information on there is up to date.
Thanks.
Here ya go, a great site with a bunch of info

http://www.steamlocomotive.com/centennials/
  by SAR RX
 
Thankyou very much for your replies Gentlemen, most appreciated.

I have never heard of that proposal Allen, you are right though, why two 12-645's? Bit of a crazy idea, but having worked in the industry nothing surprises me anymore.

Thanks for the link Jtgshu, I'll be checking it out when I finish here. I would love to see one in action, but I don't fly so unfortunately I'll never make it to the states to see one. Luckily we have some very nice EMD units over here for me to enjoy.

Cheers.
  by Allen Hazen
 
SAR RX--
Re: "why two 12-645's? Bit of a crazy idea, but having worked in the industry nothing surprises me anymore."

I don't have any sources at hand at the moment (the proposal was reported in one or another of the Australian railway-interest magazines at the time), and my memories are now nearly 20 years old! I think the motivation was fairly mundane: the potential buyer wanted a 4000 (or 4000+) horsepower locomotive, and M-K could provide 645 engines (I think they had at that time recently come up with a new (cast?) crankcase, and between that and components supplied by aftermarket suppliers could assemble all-new 645 engines with no EMD parts) but didn't have access to anything more powerful that was widely accepted in the rail industry. (They used big Caterpillar engines on their (U.S.) MK5000 demonstrator units, but they didn't sell....) So the only way they could get the desired power was by using two engines. ... The resulting locomotive would have been too heavy for general service in Australia, I suppose, but if the "request for proposals" had come from one of the Pilbara iron ore railroads, or from NSWGR with dedicated service in the Hunter Valley in mind, it might have been feasible.
  by SAR RX
 
Allen,
The thought of an M-K EMD clone with a cast case scares me, not the sort of loco I'd trust. The U.S M-K's with the CATs looked interesting though, I read a write up on them in Popular Mechanics. After the AN experience with the M-K rebuilds it seemed not many other Rail companies were to keen on them here in Australia.
I know what you mean about 20 year old memories, it's the same here with me!

Luckily I have a very good video of the Centennnials that I have just about worn out. Awesome machines, but I'm afraid I'll have to settle for the odd AN class EMD to get my fix.