1st Generation SD-series official thread (all variations)

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

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1st Generation SD-series official thread (all variations)

Post by SD45Jim »

What are the statistics for both the SD9 and the SD24? Which was the better locomotive (which pulled better, which was more dependable, etc.)?



Justin B

Post by Justin B »

Which was the better locomotive (which pulled better, which was more dependable, etc.)?

Pulled better? Well, they both would have had comparable tractive effort, but the SD24 had about 600 more ponies than the SD9 so it could hustle a train faster. The SD24 and the SD35 were the start of the evolution of the 6 motor diesel from a specialized heavy-duty/transfer unit to a universal service unit.

More dependable? The SD9. You can still see SD9s in yard service with NS and BNSF, and up until '96 SP was using them in mainline service. All the SD24s were retired in the 1970's. The turbos of course added to the maintenance costs, but the problems were in the DC/DC electrical system. Remember that EMD didn’t have a reliable high horsepower electrical system until the 40 series. The SD24 was just as complex and the SD/GP35s, which were notorious for their complex electrical systems.

Overall better locomotive? I think that’s personal preference. I don’t have any hard numbers for total sales, maintenance costs, length of service etc. but I think that the SD9 sold more, was easier to maintain and was in service longer. But I do like the looks of the SD24. Looks like a SD9 on steroids. Which it was... :P


Post by dave76 »

I like the way the SD24 looks too. Considering the naturally asperated units seem to run for ever, and turbochared units unless 3000 HP or better are usually retired, because after being relagated to branchline or yard service the turbos clog and coke up with soot due to low speed operation, turbos are ment to be screamed at high RPM.

Engineer Spike
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Post by Engineer Spike »

Recently someone asked about the difference between the SD45 and 40. I said that the 45 has a better top end. It was designed more for high speed service, replacing several Geeps. The SD24 was produced at the same time as the SD18. The 24 was better at the top end, like someone already posted. One of the engineers whom I fired for on the Burlington said that they had no top end. You can see from this that they were pretty fast. I was also told that they had problems with the relays malfunctioning in the transition circuits.
Last edited by Engineer Spike on Wed Jul 30, 2008 1:25 am, edited 2 times in total.

SD Shortline

SP SD35/E/R and SD39's

Post by SD Shortline »

What happened to the SD35's and the SD39's and are any still in service? Does anyone know if the SD35's retained the 2500HP rating when converted to the "E" or "R" status.

Here in SD I see the 2 DRGW painted SD39's on the DAIR. They are something else to watch coupled to 4 or so GP7/9/10/18/20 or whatever the DAIR runs with a 135 car rock train.

Incidentally, what would one use to back out the final 1/2" of the cylinder petcock shaft that has broken off and is stuck in inspection hole at the far end?

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Joined: Mon Mar 22, 2004 1:49 am
Location: Kentucky

Post by Bryanjones »

All of the former SP SD35's and SD39's have been retired for several years now. Some of SP's SD35's were deturbocharged when rebuilt and rerated to 2000hp for hump/yard service while others were rebuilt inkind and retained the turbocharger.

Bryan Jones

SD Shortline

An SD9E needs some help...

Post by SD Shortline »

The Dakota Southern has an SD9E, the 4427 with a little problem. One of the cylinder's petcock shaft end broke away at the threaded end. They have tried to use stud extractors, dry ice, and even drilling it out.

Does anyone have any ideas on how to extract the stud from the inspection petcock hole? Preferably, one that does not include pulling the heads.

On another note, how hard would it be to convert the dynamics on an SD9E/R to extended range braking?

The 4427 is the only DSRC unit that has operating dynamics and on 10mph track they aren't much use either way.

If they get her going again I'll post some pics of the 4427 and the 512.

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Post by snitkofj »

Have you tried an E-Z out? I'm not very familar with diesel engines (especially large ones), if you can get something reverse threaded to thread into the broken part, you might be able to get it out.

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Joined: Mon Mar 15, 2004 4:30 pm

Post by mxdata »

You have hit on most of the best choices, which are to get the biggest EZ-out that will fit into a new pilot hole drilled in the broken off stub, and weld it to the end of an extension to reach the stub. Drill the stub out to the recommended pilot diameter for the EZ-out with a long HSS drill, then drop dry ice into the pilot hole while running hot water through the engine cooling system. You can drive the EZ-out with a hammer drill to get some impact force on it. If this does not work, then you are faced with the possibility of having to break up the cylinder head in place, at least the side of it where the test valve threads in. This requires a lot of very careful drilling down from the top, and if you hit the head retainer bore you are going to have to have it welded up and re-machined. This particular job is never much fun.

GN 599
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Joined: Tue Oct 26, 2004 10:40 pm
Location: Oregon

Post by GN 599 »

I'd say the SD-9 is a better motor. They are too stupid to die! Did anybody read the January 04 issue of CTC board? They listed a few solid consists of BNSF SD-9's on the mainline, one of which had four handling a 12000 ton train! We have one where I work as a switcher and she still likes to spin her wheels! Now we got a chop nose ex-DMI&R job with anti wheel slip controls (BNSF 6137 ex-BN 6240, not sure what its DMI&R number is off hand) and its not as fun. That non turbo-charged 567 working against a cut of loads sounds pretty good though.


Post by missthealcos »

I'd say the fact that BNSF is still running a large fleet of largely unmodified SD-9's puts them high on the list of best EMD product. I can't think of any equal to them, that large a number of 50+ year old units, still on a class 1, in mostly original form, and can be found doing most anything. Pretty much anything that comes close is heavily rebuilt. Very impressive. They just don't make anything like they used to!

Engineer Spike
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Post by Engineer Spike »

I liked the SD9. When I worked for BNSF, they used 3 on the Galesburg hump. It was a pain because they had no pace setter. The trick was to put them in #3 and drag the independant.
I was on a trimmer job once. I had the 6134. It was neat doubling the class tracks for the departure yard. I jsut remember that that was a good night.

GN 599
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Joined: Tue Oct 26, 2004 10:40 pm
Location: Oregon

Post by GN 599 »

The 6125 and 6126 have pacesetters I think maybe all of the late production GN ones have them while the Q motors did not? Anyone know for sure. The only other GN ones we have had in our yard were the 6121 and 6110 but I didnt look to see if they were equipped.

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Post by Tadman »

Anywhere around Chicago or South Bend with NS or BNSF SD9's running? I think Elkhart only has SD-40 and RS11 slugs, and I don't know BNSF Chicago operations that well. I'm shocked to hear BN still runs so many. With an office on the ex-NYC/CR water level in South Bend, I'm used to only the most modern of modern power. The NS merger brought slightly older power such as geeps and high-short-hood stuff. Fun.
Dig the new rr.net Instagram account: @railroad_dot_net


Surviving SDP35s

Post by TerryC »

How many SDP35s still exist with the the extension that housed the boiler used for making steam ?
Here is one unit http://www.railpictures.net/viewphoto.php?id=40867

keep searching keep finding
http://trainiaxindex.cjb.net/ out of service 11-29-04
Last edited by TerryC on Mon Nov 29, 2004 4:16 pm, edited 1 time in total.

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