Alternative History EMD: the "SD55"

[Allen Hazen]

(((I think it is occasionally interesting to speculate about never-built, but posible, locomotive types: even that considering their likely characteristics, and the reasons for their non-appearance, can illuminate the history of real locomotives. In that spirit.... though this one seems a bit more speculative than some.)))

The EMD "SD55," which could have been introduced around 1980, is a six-axle roadswitcher, intended for heavy, fast, freight service, powered by a turbocharged 20-cylinder 645F engine. In other words, the model that would fill the gap in the proportionality
SD40:SD45::SD50:????.

Q1: What would its power have been? Since SD50, with the 16-645F engine, were built at 3500 and later 3600 hp, it is easy to imagine power outputs up to 4500. The SD45, however, had been conservatively rated, with a lower output per cylinder than the 16-cylinder SD40. Since the SD45 was rated at 120% of an SD40, and since the SD50, in the early part of its history, was rated at 3500, I'm going to guess 4200 hp for an SD55: the same as the SD45X test/demonstrator units of 1970/1971. [[QUESTION: Was the 20-645F built for stationary or marine use? And if so, at what rated power?]]

Q2: What would it look like? The SD45X gives a possible answer, but it might have been a bit more interesting. The 20 cylinder engine and the radiator needed for high horsepower eat up frame length: even with the radiator end of the hood extending so far back that the rear corner steps are ladder style, the SD45X had to be built to SDP45 length. And that's with the dynamic brakes in their less-than-optimal position over the engine. To save on length, EMD put the d.b.s there on the GP50, so maybe they would have on the SD55 as well, but if they had adopted the newer d.b. style of the SD50, the SD55 would have had to be longer. In 1980 the 80 foot length of the SD80/SD90 might have seemed to radical, but I'm going to ***guess*** at a 76 foot locomotive. ...
... Flared radiators would be a must if the length of the radiator compartment wasn't going to get out of hand. One way of saving a couple of feet would be to use larger fans (three 56inch fans would have the same swept area as four 48inch), but EMD might have been reluctant to deviate from their standard.

Q3: Why wasn't it built? This is the easy one: utter and total lack of customer demand. The last SD45-2 had been built in 1974. By the end of the 1970s some railroads were-- very tentatively-- beginning to investigate the possibilities for higher power, but the improved wheelslip control of EMD's 50-series (and GE's "Sentry" system introduced on later Dash-7) made some of them think that 4-axle units could replace the 1970s standard CC. (Most SD50 were built in 1983 or later: the GP50 outsold it early in the 50 series's history.) Finally, the U.S. was in a recession in the early 1980s (Conrail was able to make major locomotive purchases in 1983-1985 because the builders were desperate and offered super deals!): by the time the economy recovered, EMD had given up on the problematic 645F and introduced the 60 series with 710 engines (no 50 series units were built for U.S. railroads after 1985).

[Bryanjones]

well fact is that there was almost an "SD55". While the SD45X was a test model for many features which would become standard on the DASH 2 locomotive models which went into production in 1972, it was also a testbed for a new high horsepower locomotive powered with the 20-645 prime mover. While the SD45X testbeds tested extensively on many roads before 6 of the 7 units ended up on the SP, there just wasn't any demand for the 20 cylinder, 4200hp beast. Many railroads had already been soured on the 20-645 by the time the DASH 2 series came along due to crankshaft problems (which had been solved) and higher fuel consumption. The 6 units which ended up on the SP ended up being derated to 3600hp and were all retired by about 1980. Had the SD55 actually made it into production it would have been the first production, single engined' locomotive to break the 4000hp barrier, which in the end wouldn't happen until the early 1990's. Hell it was 1987 before the first production model locomotive would be rated at 4000hp, the GE C40-8. The concept for the 4200hp, 20-645 powered loco just came along at the wrong time.

Bryan Jones

[GOLDEN-ARM]

A six axle road switcher? There is the problem, right there. Railroads don't buy road switchers anymore. All high horsepower, road freight locomotives. The need for a road switcher is easily filled, by an older unit, allowing the money you have to spend going to buy faster, more powerful road units. The last road switchers I would say were sold, were GP-38's, and SD 9's and 18's Turbocharged engines don't lend themselves well, to the duties of a switcher, whether on the road, or not. Just my .02 cents, though.

[AmtrakFan]

There was talk about MRL rebuilding some of there SD45's to SD55's.

[Allen Hazen]

Thanks for your comments!

--- Bryanjones: The SD45X was an interesting experiment. SP (they had the largest SD45 fleet, didn't they?) was interested enough to cooperate with EMD on it, getting three initially and then buying three of EMD's four. (I think they derated them to 3600 hp after a while, and used them as if they were ordinary SD45: more information would be appreciated*.) The engine in the SD45X was an uprated 645E (with, I think, a number after the E to distinguish it from the production engine): the 645F, a few years later, had some new features (of which I can remember a slightly elliptical crankshaft cross-section for better lubrication).
...EMD, in its public statements, insisted that the SD45X were test locomotives, and NOT a new model being offered to customers. (I'm sure they would have been willing to build more if someone had offered to pay them, though!) ... MLW, on the other hand, CLAIMED that the M-640 was a catalogued production model, even though they only sold one! GE cautiously waited until 1970 before selling U36 models, but around the time the SD45X was built it was reported in "Trains" that the FDL engine had been operated at over 4000 hp on test stands. The long delay before North American railroads started to acquire 4000 hp locomotives in quantity is an interesting historical phenomenon....

-- Golden-Arm: Apologies if I was confusing in my nomenclature: I was just using "roadswitcher" to mean hood unit. ... You're right about there not having been any roadswitchers, in the original sense, produced in quantity lately. EMD tried with the BL-20-2, GE tried with the B23-7S, but railroads still seem to want GP-38: witness Norfolk Southern's program to rebuilt GP-50 as GP-38-3. (The "GP38 replacement" might seem almost as chimaerical as the "DC-3 replacement" that various aircraft companies tried to make after WW II!)

-- Amtrak Fan: I didn't know about that. A number of railroads-- Santa Fe among them-- re-engined a small number of SD45 with 16 cylinder 645F, making them "virtual" SD-50. Are you sure this isn't what MRL had in mind?

---
* If you have information, and (particularly) photos of the SD45X, get in touch with "CYC Board" magazine: their July 2005 issue had a note soliciting pics of these locomotives!

[AmtrakFan]

I read it in a Issue of Trains Magazine I think it was the April 1993 issue.

[Bryanjones]

Allen,

Yes the SP did have the largest fleet of SD45's (356 units to be exact I believe), not to mention the entire production run (247 units) of the SD45T-2, 10 SDP45's and ofcourse the 6 SD45X's. just over 600 20 cylinder units total. Yeah, SP was a big player in the SD45X development with 3 of the demo units being built completely to SP specs. During the mid to late 1970s' the SP SD45X's were infact derated to 3600hp to standardize them with the rest of the 45 fleet. Once they finally went in service as SP units they were treated just as the rest of the 45 fleet. Yes EMD did try and claim that the SD45X's were not test units for a new model but had that truly been the case I doubt that such a unique locmotive would have been built to test and showcase the latest technology, such as the new DASH 2 electrical cabinet and the new HT-C truck. It just doesn't make sense to build 7 unique, 4200hp testbed locomotives unless your intentions were to introduce a new model based on this test unit.
I do recall that MLW did offer the M640 as a production locomotive, with CP buying the only such unit built. With complaints over the performance of the M630's and M636's its obvious that the M640 was really stillborn and never really had a chance of being built in quantity.
Yeah GE did test the FDL at 4000hp in the late 60's, though it wasn't until 1987 that a production GE locomotive hit the floor that was rated at 4000hp. The early GE U-boats weren't that great and the 3600hp U36B's and U36C's were never really compeitive locomotives when compared to comparable EMD units.
Really all railroads had retreated to the 3000hp loco as the mainstay of the fleet as the railroads realized that anything higher than 3000hp just wasn't practical during those times with higher fuel consumption, increased maintainence and less sophisticated wheel slip control was available.

Bryan Jones

[Allen Hazen]

It sounds, Bryanjones, as if you know a LOT more than I do about the SD45X....
(Thanks for informative reply.)
--
AmtrakFan-- I don't have ready access to old issues of "Trains." (If someone else does, and would like to check the April 1993 issue....)

[N. Todd]

Yeah GE did test the FDL at 4000hp in the late 60's

Gross output or for traction? But yeah, you can crank alot outa the FDL, after many years of improvement.

I do recall that MLW did offer the M640 as a production locomotive, with CP buying the only such unit built. With complaints over the performance of the M630's and M636's its obvious that the M640 was really stillborn and never really had a chance of being built in quantity.

The M-640 was in fact catologed... I don't know why, after all, they're advertising the unit that failed on it's madien voyage, in front of the MLW officials- in effect, rubbing it in. Had MLW listened to their customers, shipped on time, and diligently worked on correcting the flaws (as GE did) they might have sold a few.
Now what exactly caused the crankshaft failures in those 18 & 20 cylinder locomotives?
And how come there were never any V-14 prime movers?

[Allen Hazen]

N Todd--
From what others have said, the big problem with crankshafts in the 20-645 used on early SD-45 was with the supports: the problem was largely solved by a more robust design for the area of welding the crankshaft supports to the floor of the crank case ("D-foot" was I think the term for the revised design).
As for 14-cylinder... My guess is that nobody saw any need to engage in the new engineering involved: the engines were available at a range of ratings, and there wasn't that much difference between the output of a 12-cyl at "top" rating and a 16-cyl at lower rating. Example: the GE 16-cylinder engine in a U30 gives a 3000 hp locomotive. The 12-cyl version, rated at the per-cylinder output of the engine in a U36, would give a 2700 hp locomotive, and GE experimentally provided a small number of U23B to the L&N at the higher rating in the early 1970s.
That said, there was one experiment with an effective 14-cyl engine: GE built two U30C for UP in which the last crankshaft throw was used to power an air compressor built integrally with the engine block, with the full normal (I think) power coming from the remaining cylinders.

[U-Haul]

I plan on having SD55s on the layout in about 5 years. Take GP60(M) 710 prime movers out, rebuild them to Tier Two specifications, and put them in SD50s. (Still rated at 3,800 horsepower.)

[mxdata]

Allen, going back to your original question, the 20 cylinder 645F engines were indeed cataloged items for the marine and industrial market even after the 710 became available. Somewhere in my archives I have all the rating information, when I get a chance I will see if I can locate it.

[MEC407]

I plan on having SD55s on the layout in about 5 years. Take GP60(M) 710 prime movers out, rebuild them to Tier Two specifications, and put them in SD50s. (Still rated at 3,800 horsepower.)

Wouldn't that be an SD60 then, not an SD55?

If you took the 645F in the SD50 and rebuilt it with a higher horsepower rating, I suppose you could call it an SD55. But if you're using a 710, the number really ought to be 60 (or higher).

[Allen Hazen]

U-Haul--
I wonder if there will be a prototype for that conversion...

GP/SD-60 are not candidates for conversion to "GP/SD-38-3" in the way BP/SD-50 are: de-turboing a 710 engine wouldrequire special order (and newly designed) parts. The conversion you describe, however, might be feasible.

The 710 engine is (I assume, given that the cylinders have the same bore) the same length as the 645, and given EMD design philosophy probably a lot of other things are compatible. Does anyone know what would be involved in re-engining a 50 series EMD with 710 engines? Would you need to install all-new radiators, or would speeding up the fans be enough to cool the more powerful engine?
--
mxdata--
Thanks in advance! The only marine application I know anything about was in the tugboats (different tugs, but of the same class and I think belonging to the same towing company) that towed the battleships Missouri and New Jersey from the ports where they were in reserve (Newport and Puget Sound) to their current museum sites (Pearl Harbor and Delaware bay). They were described as 7200 hp boats, with two 20-645 each -- but whether this means that the engines were actually rated the same as in a 3600 hp locomotive i have no idea.

[mxdata]

Allen, I found the 645F specification book. The common power generating rating for the 20 cylinder 645F engine was 4000HP at 900 RPM versus 3600HP at 900 RPM for the 20 cylinder 645E engine. Note that power generating requires synchronous speed (900 RPM) compared with the usual "50" series locomotive maximum of 954 RPM. Sorry for the delay, I am reorganizing the file system and this stuff is all in piles right now.

In respose to your question about substituting a 710 for a 645, the mounting footprint, crankshaft couplings, and pump piping connections are in the same relative positions for both engine models having the same number of cylinders, but the 710 turbo air inlet and exhaust outlet are positioned differently from the 645. Heat rejection to lube oil and cooling water are going to be different and would have to be calculated to see if the cooling system components would still be adequate.