• History of the E-unit

  • 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 MEC407
Oops! I forgot about Baldwin. I ALWAYS forget about Baldwin. :wink:
  by Allen Hazen
About Baldwin and a possible E-unit-like locomotive with twin 16-567...
Among the many imitators of EMD's E-units (Alco, Baldwin and F-M all built streamlined A1A-A1A passenger units in the 2000 hp range in the 1940s), the earlier Baldwin examples (units for N de M, GM&O, and CNJ) show that the length and weight issues, though serious, wouldn't have been insurmountable. These units all had inline 8 cylinder engines: non-turbocharged, so only 1000 hp each, but still I think bigger and heavier than a 16-567. They were a lot heavier than an E-unit (though still not as heavy as modern C-C freight diesels) and at least several feet longer, but obviously within the clearance and weight limitations of North American railroads in the 1940s. In principle, then, I think they could be used as the outline for a design of a unit with twin 16-567. Continuous speed would be high, and wheelslip probably bad, but with the big Westinghouse traction motors they used, they probably could have worked as 3000 hp units in high-speed passenger service.

Later in the 1950s there was 3000 hp twin-engined, six axle, diesel built for express passenger service: British Rail's (Class 55) "Deltic." This was a C-C rather than an A1A-A1A unit, but built for use in Britain, so MUCH lighter than an E-unit (about 110 (US) tons as opposed to 150/160), and fitting into a very restricted loading gauge. This was accomplished, however, by using light-weight, high-speed -- and so high maintenance -- diesel engines.
  by MEC407
Excellent information, Allen. :-D
  by mtuandrew
TSTOM, it sounds like you're trying to design a passenger version of the DD35A. :grin:

It might have worked, especially if EMD had used eight axles underneath rather than just six, but it would have been a behemoth and probably not worth the added expense. That didn't stop Baldwin from trying with the Centipede (or the M1 or Jawn Henry steam-turbines), but EMD seems to have been much less willing to build a custom piece at that time. Even the oddballs - the AB6, the export models, the DD series - used common components from their parts bins, aside from frames.
  by Engineer Spike
Baldwin was desperate. This is likely why they came up with strange designs. 3000 HP may have been too much for the A1A wheel arrangement. E units were supposedly slippery as it was..They might have had to go with CC, all axles powered. Wheel slip control was not to advanced then.

This is why some lines stuck with passenger F units. The division of the passenger locomotive market between the E and F series would have made such a major redesign to expensive for GM to consider.

On a similar note, I have a book about the rebuilding of D&He's PA fleet. They replaced the 16-244 with a 12-251. A 16-251 would have fit, but the mods to the support systems would have been too great. They even had to derate them at lower speeds because of wheel slip, on account of not having 100% weight on drivers.
  by Allen Hazen
Engineer Spike--
I think I used to have a copy of that book about the D&H's "PA-4" locomotives! Not sure what happened to my copy....

As to the unfeasibility of 3000 hp with the wheelslip technology of the E-unit era... For most applications in the U.S., yes, and most railroads wanted a locomotive fleet that could operate in a pool (so all their passenger units had to be able to cope with many different runs). But suppose, as a counterfactual, that some railroad had been willing to spend money on a small number of a special type for use ONLY on trains with sustained high-speed running on fast track. (So, pretend the Milwaukee had bought a few super-diesels to replace their streamlined Hudsons on the Hiawathas, or that the New York Central had been willing to stable a special bunch of horses for exclusive use on the 20th Century Limited: economically lunatic things to do, but just suppose...) Then, I think, a 3000 hp "Super E" might have been technically successful.

Compare the British Rail Deltics. They were a bit later (prototype built in 1955), but I doubt they had wheelslip control much more sophisticated than an E-unit's. (U.S. locomotive builders didn't really start improving wheelslip control until the 1960s, I think.) And they were very light! The Deltic prototype weighed 106 long tons-- say about 118 U.S. tons-- which isn't all THAT much more than an E-9's 110 tons (I think) on the drivers. And they were very successful! But not used in general service: no locals, no commuter service, no runs over the Pennine mountains, just the London to the North of England and Edinborough expresses on the East Coast Main Line "racetrack."
  by Typewriters
At the time Baldwin was converting from the VO to the 600 series engine, it designed and offered to the railroads but did not sell 3000 HP, A1A-A1A locomotives in full streamlined carbody in either cab or booster configuration. These were in practical aspects exactly parallel to the range of 2000 HP locomotives that were actually built (the VO demonstrators and added unit for NdeM, and units for Jersey Central and GM&O) generally speaking, but with turbocharged eight cylinder engines (608SC) instead of normally aspirated ones. These units are illustrated in a trade catalog in my collection, which does illustrate both 2000 HP and 3000 HP A1A-A1A units. The Westinghouse 370 motor was fully capable of developing the 750 HP per motor that the design would have required (and it actually did so a few years later in the experimental electric locomotives built for operation on the Pennsylvania in both C-C and B-B-B wheel arrangements.)

The units of course would have been quite heavy -- but not significantly heavier than the units actually built.

-Will Davis
  by Allen Hazen
Will Davis--
Thanks for that information! ... Listing something in a catalogue doesn't have to mean they had worked out the detailed design: it might have been a case of "Well, one thing we COULD work on would be... Why don't we put a picture in our catalogue, and if anybody expresses interest we'll go to work on it." On the other hand... Except for putting a bigger cooling system into their 2,000 hp passenger unit carbody, and telling some of their best electrical engineers "Wheelslip: now we are locking you into the office for the weekend; tell us something on Monday," this seems like a straightforward project, recombining constituents used in other models. So I think do-able! ... Even the horsepower-per-powered-axle rating (750 on a 3,000hp A1A-A1A) is something Baldwin had already thought about: the multi-engined wartime prototype that donated its running gear to an early Centipede would have been 6,000hp with eight motors if it had had the full intended complement of engines installed.

Heavy, certainly. And I (trying to think like a civil engineer) don't like the idea of heavy units at passenger train speeds. But would it have been any worse, per axle, than the current generation of 4-axle commuter locomotives?

((((B.t.w. News item and photo in July 2013 "Railfan and Railroad": the last surviving Southern Pacific K-M diesel hydraulic has been cosmetically restored. Do you have more you would like to tell us about these locomotives that you haven't posted on your Blog?))))
  by Typewriters
The locomotives are described as "available," meaning (to my mind, anyway) that they were available upon issuance of, and acceptance of, specification and bid in contract with a customer. There was in all likelihood nothing in the design of these locomotives not already built for road service, including the trucks and carbody design. The major alteration was the inclusion of a turbocharged instead of normally aspirated engine. (Of course, the main generator would have changed from the 480 model used on the 2000 HP units to the 489 as was found in Seaboard 4500, and other early units with turbocharged eight-cylinder engines, or else the 471.) So it's safe to say that no additional design work beyond what had already been built would have been required.

Getting back to the original intent of this thread, though, it seems significant to point out that what might have been a design path taken by any exercise at EMD to equip an E-unit with 3000 HP at that time was not pursued when actually offered by Baldwin. These would have had more weight on drivers, in a pair, than a single equivalent Centipede - roughly 520,000 lbs for the two A1A-A1A units against 410,000 lbs for a single Centipede. Their adhesion in freight service would have been improved, clearly - but no road bought Centipedes for what we might think of as conventional heavy freight service, since PRR bought its units as passenger locomotives and SAL and NdeM used their units on lines with low axle load limits. From a mechanical officer's standpoint the 3000 HP A1A-A1A unit would have been better than the Centipede, it looks to me - and still the railroads plowed forward with what we think of today as wholly conventional road freight locomotives, with the F-M Erie being the sole exception. It might be oversimplification to say that tractive effort ruled the day, as train speeds still remained low compared to what we think of today, but it's probably quite accurate.

I believe it's exploring the relationships such as this which get at the heart of why EMD would never have bothered to try to offer any such dual engined 3000 HP locomotive -- especially more if one considers Kirkland's quotes of Dilworth on negative qualities of the Centipede.

A much more fun idea I think would be a kitbash to depict an E-8 or E-9 repowered with two 1500 HP 12-645E engines and D77 traction motors. Maybe even give it AC drive for full parallel motor operation at all times, and IDAC wheel slip control. But that's the extent of my speculating tonight!

-Will Davis

PS Yes, Allen, I'll dig around for more K-M info!
  by Allen Hazen
I can THINK of some reasons why EMD stuck with the E-unit configuration, though I don't know if they actually considered a change to something like what you suggest.

(1) The engineering work for anew engine is probably at least as hard (and time consuming, and expensive, and risky) as that involved in designing a new locomotive around existing power plants. A V-20 version of the 567 would certainly have been possible-- as we all know, the 645 and 710 had been built in V-20 configurations and successfully used in locomotives. But it would have seemed like ... stretch, if you'll pardon the pun. The long crankshaft would have been a pain to get right, and might well have been thought of as a risky design. (Recall also that the early SD-45 had engine problems that had to be resolved by some redesign work, notably increasing the area of the welds joining the crankshaft supports to the engine base.

(2) Power. EMD wanted to match the 2200 hp that Alco was offering with the upgraded (1950 version) PA, and not to fall too far short of the 2400 of Fairbanks-Morse's CPA-24-5. When the E-8 was introduced, the highest ratings they were willing to give the 567 in locomotive applications was 100 hp/cylinder. A V-20 wouldn't have quite enough oomph.

(3) By the time the E-9 was introduced in 1954, the market for streamlined passenger units was thin enough that they may not have thought investing serious development efforts into it was worth while. (The E-9 sold many fewer units than the E-8 even though it was in production about twice as long.)

(4) American railroads are intensely conservative and cautious in what they buy! They had leaned to love the E-unit: persuading them to adopt a new type with a new engine, even if it offered some advantages, would have been a task.

But, as I said, I don't know whether they actually considered the issue.
  by RSD15
Qwerty, what you are describing is essentially the FP7/9 that was sold by EMD. Not quite the power of the E units they topped out
about 1750/1800hp with a 16 cyl 567 engine. Many roads roads owned these across the US and Canada.
  by MEC407
I think the logical evolution for the E-series would've been to switch from the twin 12-567s to a turbocharged 16-567... or maybe even a pair of turbo 12-567s.

EMD's first turbocharged locomotive was the SD24 in 1958. At 2400 HP (150 HP per cylinder), the turbo 16-567 would've been a pretty reasonable replacement for the non-turbo twin 12-567s.

A year later, they introduced the turbocharged GP20, with a slightly more conservative 2000 HP rating (125 HP per cylinder). A pair of turbo 12-567s at that same per-cylinder rating would've produced a total of 3000 HP. That might've been a stretch for EMD's traction motor technology at the time... but maybe they would've figured it out. After all, it was only six years later that they were building the 3000 HP GP40.
  by Allen Hazen
RSD15 and MEC407(*)--
Both good replies to Qwerty's question!
RSD15: this, if anything, confirms the thought behind my answer. EMD was happy to provide an alternative to the E-unit... using an engine they already had and were applying in standard, mass-produced, units. The carbody modifications (four feet extra length over the F7/F9), even though they involved a change in the truss structure of the F-unit framing, were easier than coming up with a new engine configuration.

MEC407: Yes, the single turbocharged engine (like Alco's!) would have been a better way to get the added power for an E-unit equivalent, as witness Amtrak's purchase of SDP40F and F40 (both powered by turbocharged 16-cylinder engines)in the 1970s instead of an "E-10" with twin 12cylinder engines. (An article in "Trains" at the time said that Amtrak would have liked an "E-10" but that EMD refused to make one.) But, as you note, EMD's turbocharged engines were a few years late for an alternative to the E-8 or E-9. ... By the 1960s, EMD was using turbocharged V16 engines for passenger units: GP30B with steam generators for UP, and SDP35 for several customers. This allowed them to drop production of the (high production cost? the truss frame must have been labor-intensive!) E-series.

(*) What does it say about locomotive history that the interesting comments on an EMD forum are from people who refer to Alco and GE locomotives in their noms d'internet?
  by JayBee
Allen Hazen wrote:Comments:

(*) What does it say about locomotive history that the interesting comments on an EMD forum are from people who refer to Alco and GE locomotives in their noms d'internet?
Yes but, Alco would have gladly traded being thought of as innovative and stylish, for EMD's sales numbers and profitability in that era. And how many now feel that GE's current production, limited to ES44AC and ES44C4 locomotive models in North America is dull and boring.
  by MEC407
JayBee wrote:...Alco would have gladly traded being thought of as innovative and stylish, for EMD's sales numbers and profitability in that era.
True, and I suppose that's how EMD has been feeling lately when they see how well GE is doing, both in North America and worldwide. Not that I'm suggesting that EMD is today's Alco. Alco fans would rightfully take umbrage at such a statement. :wink: