EMD SD40 series official thread (covers all variations)

[dash7]

Thanks for the replies,I guess I am just thinking wrong locomotive for the railroad at the time weren't the water tanks a 50/50 fuel tank Ala fp45 or were they somewhere else?, cheers Derek

[Mr. Know It All]

I am NOT saying there was never a "unique" truck, that was before my time. But, EMD has 2 test units out at the TTC in Pueblo that were former Amtrak SDP's. They have the "original" trucks and I will be darned if I could tell any difference in terms of appearance, spring types/locations, pedestal jaw measurements, etc. They have the same "HTC" casting emblem like all others that were cast by Rockwell at that time. If there was something "special" about these trucks, from a maintenance standpoint I dont know what it is. Someone willing to examine an EMD 190 parts catalog could research it further to verify.

I am not around the units anymore but suggest you get a close up look for the casting/part number on the truck sideframe on an SDP and then look at a "regular" HTC of the same vintage and compare. Dont jump to conclusions too fast though as I am sure there are many different casting numbers from the 1960's to "today" and with the way trucks get swapped around, even then it may be inconclusive. I do however think it is very safe to say that MANY HTC trucks from SDP's have wound back up in service being purchased from independnt shops as "used/rebuilt".

As info, the 2 former SDP's out at Pueblo run just fine with no speed restrictions and if anything, are even worse for balanced weight at the steam generators has been removed and diesel generator sets and equipment "labs" installed. All this stuff is "off center" on the conductors side to allow a walkway on the engineer side.

Yes, SDP's were "freight engines". From a track geometry standpoint, they should be run at "freight" speed. Most of the time, people think the higher speed for passenger trains is only to reduce travel time. While true and the fact that passenger cars are much "smoother" on crap track, the SDP was not designed as a "true" passenger locomotive. (ala A-1-A or B-B trucks).

6 powered axles are designed to handle more amperage at low speed (below 12 mph) without overheating traction motors. This is never the case on passenger trains due to speed and light tonnage. The extra maintenance of a 6 powered axles (such as maintaining wheel measurements to FRA requiremnts, brushes, gearcases, pedestal liners, brake rigging, et all) makes no sense IF the unit will NEVER go into freight service at any time before getting cut up.

In short, a 6 axle locomotive is basically a waste for passenger operation BUT has tremendous value when it comes time look at resale value. Think of it as buying a 15 year old pickup to pull a large trailer. All else being the same, would you want the one with or without the "trailering package" and would you be willing to pay as much for the the one without it?

I think if you ran ANY SD type unit at passenger speeds back then in the eastern US, it would have suffered the same fate....but that is just my opinion.

[Allen Hazen]

Thanks again, Mr. know-it-all, for another very informative post! (I've just clicked on your name to find your posts in a number of different forums: all interesting.)
--
My original source for the idea that the SDP40F had a unique truck was the same Kalmbach Press "Diesel Spotter's Guide" entry, and we know that that series, valuable though it is, contains errors. It referred to the SDP40F truck as a "hollow bolster" truck, suggesting that if there was anything unusual about it it was the bolster: for all I know there MIGHT be something special about SDP40F trucks but something that allowed them to use identical truck-frame castings to those used on (non-Conrail) SD40-2. All a bit mysterious to me, and I'm not sure how even to start going about getting the information to sort it out!

[bogieman]

The HTC was designed in 1968 with two interchangeable bolsters - a solid and a hollow bolster, the solid bolster weighing about 5,000 lbs more than the hollow. The two bolsters have identical outside dimensions, the hollow one is simply cored out in the whole H section and can be identified by the core holes not present on the solid. The purpose in having two different bolsters was to be able to build a lighter loco or compensate for the weight of other equipment to keep the loco weight at the desired level. All SD40-2's, SD50's, and SD60's got the solid bolster simply to make the loco weigh what the customers wanted. Those units had a lot of extra weight in the underframes that was not required for strength and was simply there to get the total weight. It was cheaper to buy the weight in the cast bolster than to add it as ballast so that's what was done. To keep the weight of the SDP40F at 390,000 lbs. given the water and fuel it carried, the hollow bolster was used, along with a thinner bottom plate on the underframe. I don't recall what bolster the F40C's got but probably the solid since it did not carry water.

The hollow bolster was also used for export applications of the HTC, such as the Foster Yeoman JT26CW-SS Class 59's and Saudi SDL40-2's. IIRC, the SD45X units had one solid and one hollow bolster to balance the loco weight between trucks.

As far as the root cause of the derailments of the SDP40F's, there is much speculation but all the experts of the day could not find any design problems in spite of months of instrumented wheelset testing. The hollow bolster had absolutely nothing to do with it, however.

Dave

[bogieman]

To clear up one item, the FP45's used SD Flexicoil trucks which have a different motor orientation than the HTC which replaced it in 1972 with introduction of the -2 series. In my opinion, the SD Flexicoil would have been a better choice in hindsight since it has considerably more total vertical suspension travel which makes for a better ride, although it is poorly damped with friction dampers.

The HTC as originally delivered on the SDP40F's and other -2 units before 1975 was known for rough ride, particularly laterally. In 1975 the secondary springs were softened laterally and the lateral truck frame to bolster clearance was increased from 1.25 to 1.75" per side to help the lateral ride. A maintenance instruction, actually called a Modernization Recommendation, was issued to rework the clearance on existing trucks. For locos geared for over 70 mph, lateral dampers were also recommended and a retrofit design developed. The primary vertical damper at the center axle positions was also increased in output by 50%, changing from a through-bolt mount to a bar mount. But these changes did not change the wheel-rail forces, only the carbody response.

Dave

[dash7]

Bogieman,
Thanks for your informed reply and I was never aware that the hollow bolster was used for a weight saving measure ,but in hindsight it makes sense to have that option on the Amtrak SDP40F'S as they did carry a lot water let alone the weight of two steam generators!another point i wasn't aware of was the lighter underframe, again thanks for the response to this some what age old mystery, cheers,Derek

[Tom6921]

With CN having retired the first SD40 (IC 6071), has any museum expressed interest in acquiring it? It is histoically significant because of how popular the SD40 and SD40-2 were when they were new.

[SSW9389]

I think I read it is going to IRM. Anybody else have a clue?

[SSW9389]

It also is historically significant because it is the first unit equipped 645 engine. It put a 3000 horsepower alternator drive in the field fully one year before the ALCO C630. This locomotive should have braggin' rights to something.

With CN having retired the first SD40 (IC 6071), has any museum expressed interest in acquiring it? It is histoically significant because of how popular the SD40 and SD40-2 were when they were new.

[Triplex]

Can anyone tell me how I can figure out which nose length's are on 2 SD40-2's? NYSW has a former NW SD40 and a former Southern SD40-2 both originally high hoods. Both have been fully rebuilt from the trucks up. Im trying to figure out if they are 81 or 88 inch nose's.

Didn't all high-nose EMDs have 81" noses, even after the change to 88" as standard?

[atsf sp]

What is happening to BNSFs SD40-2s. There roster now has SD39-2u where the SD40-2 were with a few sd40-2 in between clumps of these sd39-2us. Why are they rebuilding?

[Triplex]

I believe the SD39-2u are intended as heavy switchers. BNSF has enough modern mainline power that they don't need SD40-2s for that anymore.

[trainiac]

Steve F45 wrote: Can anyone tell me how I can figure out which nose length's are on 2 SD40-2's? NYSW has a former NW SD40 and a former Southern SD40-2 both originally high hoods. Both have been fully rebuilt from the trucks up. Im trying to figure out if they are 81 or 88 inch nose's.

Didn't all high-nose EMDs have 81" noses, even after the change to 88" as standard?

From what I've seen in photos, both units in question were built with 81" noses (not an issue with the former NW SD40) and retained 81" noses after rebuilding.

[Mr.S]

Doesn't the N.Y.S. & W.RR also have EX SP/ EX u.p. rr SD40 - T2's and SD45-T2's? I seem to recall seeing some painted and lettered for N.Y.S. & W. RR

[charlie6017]

I know they have the SD40-2T's---not sure about the '45s.