Will, I agree with the balanced history. I think that the more information we can pass on to the future, the better. The internet makes it so much easier, such as your blog. Excellent work. I found some pictures of GE 750 in UP paint, but the site is down now so I can't link them.
Gentlemen: Great discussions. I'm just getting back into train watching after being out of it for about 30 years. (now you know about how old I am) I just found this sight today.
Question: What is the 'Tags' thing all about?
Thanks! This gives even more to check with the Eesti Raudtee fleet management. Though I doubt these guys agree because the Russian locomotives must use even more lube oil.
DwightBranch Santa Fe sold their 8000s/ C30-7s early, around 1992, when they were only 15 or so years old. I remember the first one I saw with the numbers and Santa Fe name painted out in 1992, it was a surprise at the time to becasue they were so ubiquitous, they seemed to lead most fast trains then, not 199/991 the UPS train which got the newest four axle power, but 981 the perishable train for instance. 5100s/ SD40-2s were more popular with crews but the 8100s were quieter and were almost always on the point in the 1980s. What I heard at the time was that the railroad was mad about high lube oil consumption (lube oil is expensive) and excessive/ premature power assembly wear, and was unsatisfied with the solutions offered by GE.
Santa Fe sold their 8000s/ C30-7s early, around 1992, when they were only 15 or so years old. I remember the first one I saw with the numbers and Santa Fe name painted out in 1992, it was a surprise at the time to becasue they were so ubiquitous, they seemed to lead most fast trains then, not 199/991 the UPS train which got the newest four axle power, but 981 the perishable train for instance. 5100s/ SD40-2s were more popular with crews but the 8100s were quieter and were almost always on the point in the 1980s. What I heard at the time was that the railroad was mad about high lube oil consumption (lube oil is expensive) and excessive/ premature power assembly wear, and was unsatisfied with the solutions offered by GE.
Nobody seems to have commented on the second rating of the 12 cylinder shown on the cover of the GEA-10016 Brochure.
Just below the B23-7 caption is what appears to be B28-7 (or possibly B26-7), it isn't that clear in the reproduction, even as enlarged.
There was of course the 2600 HP rating in export locomotives dating back some time, but this is clearly what eventually appeared as the B30-7A, there being little interest in intermediate ratings, as EMD found with the GP49.
M636C.
M636C: That's indeed the B28-7, and there's a C28-7 listed as well.
As to the PC U33B's dropping load when notched out.. I believe that these units were too early to have CHEC Excitation, but they did have the simple pressure-bias governor that fuel limited based on intake manifold pressure. (Single slope pressure-bias governor.) I'll look more at the manufacturer catalogs and manuals later today but I see either BCO65 or BCO80 turbochargers for these as new (these are Elliot turbos, not GE turbos which appeared in 1976.)
Does anyone out there have a firm date for when CHEC Excitation was introduced? I cannot find a firm date in literature. I have seen patents as early as 1973 for it; I own a large GE manual which has a section for these two turbochargers dated 1972 and there's no mention of the speed sensing probe. This situation is a bit murky later on as CHEC turbochargers could be backfitted to many models, and kits were issued to install CHEC excitation components into turbochargers that didn't originally have the components. GE also offered unit-exchange CHEC excitation turbochargers.
-Will Davis
Railroad Locomotives - My Blog
Checked a bunch of documentation last night; had constructed a gigantic post but it was all part numbers and what not -- probably very boring to read.
PC's U33B units were all built prior to 1972 and so would have had the 400 Hz transistorized excitation system, BCO65 (Elliott) turbochargers with no CHEC excitation, and Woodward governors with two slope pressure bias load control scheme with the modulating input being intake manifold pressure and not turbo RPM.
The turbo speed module card on CHEC has a micro selector switch for either an Elliot or a GE turbo.
Will DavisChecked a bunch of documentation last night; had constructed a gigantic post but it was all part numbers and what not -- probably very boring to read.
Maybe so... but please post it anyway...
Overmod Will DavisChecked a bunch of documentation last night; had constructed a gigantic post but it was all part numbers and what not -- probably very boring to read. Maybe so... but please post it anyway...
I'd like to see it as well.
All right.. you asked for it! I had it built on the word processor so luckily it was saved. Original post below but with a couple of edits / additions.
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I did a bit of checking as to the excitation and governor fitting that the PC U33B units would likely have had and came up with the following.
First, a quick look at a roster at The Diesel Shop website shows all of the PC U33B units having been built between 11/68 and 6/70. (I don't have anything in print on PC diesels here for a roster - NYC, PRR yes but I cut off at the start of PC.)
Using that information, a quick check of GEJ-3866, Educational Manual / Model U33 Diesel-Electric Locomotive published 1/71 (and also identically republished 2/73; I have both) tells us that the U33 had the 400 Hz transistorized excitation system; this did not have an input for turbocharger speed. (For you tech guys, this is a pulse width modulation system.)
Looking at GEJ-3869, Diesel Engine Mechanical Service Manual, Diesel-Electric Locomotive published 5/70 (and which covers models U23, U30, U33 and U36) we find application of a two-slope pressure-bias and load control limiter model governor.
This sends me, out of sheer curiosity, to the handy Locomotive Unit Exchange and Repair Services manual, from which it's the easiest to figure out what original equipment was fitted on locomotives in a generic sense. I see several models of governor applied to U33 locomotives; but since part numbers always go up in GE nomenclature as parts get newer, we can examine the first few models even if we don't have dates. Or, seeing the wide variety, maybe just the first model...
Model 136X1740 is listed for U33 and U36 in one table; in a second that governor's 1977 unit exchange replacement, the 136X1740-5R is described under the heading for "Chec excitation" as NO, and under the heading of "Air Sensing (Pressure Bias)" as Yes - Fuel Limit. (That matches what is described in GEJ-3866 and GEJ-3869.) This however doesn't really illustrate the fact (fully explained in excruciating detail back in GEJ-3869) that the governor will act, upon having too low an intake manifold pressure for the given speed, to limit excitation first before it begins to limit (reduce) fuel by operating the ORS linkage. This -5R however is a modified version of the governor and might not be original or rather identical to original models. (Note the "R" suffix.)
So, trying to see if I can come up with any useful data on this governor originally or later versions of the original (prior to the Unit Exchange program) I then get out GEK-30130 which is a big heavy Conrail-specific manual for its GE locomotives' diesel engines and systems. (It covers all Conrail GE locomotives, including those from all previous owners and also Conrail units up through I think the C30-7 purchase.) Sure enough, in instruction GEK-29332 I find on page 3 that same governor model - the original one - listed for the U33. (It also applies to the U36 - both have engine speed schedule "C" which means 1050 RPM maximum.) I then track that number to GEK-29462H, Governor Data which includes "data pertaining to two-slope pressure bias control, those equipped with fuel limit control, and those equipped with altitude compensation" and find not the original but do find a 1740-1 which fuel limits at 49 inches Hg absolute manifold pressure and has an 11-13 psi low water shutdown (integral in the governor); a 1740-2 which is the same as the -1 but adds dual speed load control timing; a 1740-3 which is the same as the -2 but adds a 46 psi lube oil shutdown; a 1740-4 which is the same as the -3 but has lowered pressure-bias settings; there's no -5 but the -6 changes to a 12 pin connector (and replaces the -5) and also omits the No. 1 pressure bias setting screw. The 1740-7 is the same but adds an ORS lever.
So the original governor with no appended model number must have been very quickly superseded and deleted, judging by this drive through the weeds of part numbers. Nowhere in any of that does CHEC appear, although there are a number of other governors that were available for the U33 over time that came after this 136X1740 range.
Right now the biggest hint that I have which tells me that the CHEC excitation appeared when the GE turbochargers appeared is the fact that none of the GE turbochargers of any model are available (in the 1978 Unit Exchange manual) without CHEC excitation, whereas all of the previously used Elliott turbos are available with or without (and there are details on converting the Elliott turbos to CHEC excitation not only here but in other manuals.) So right now that's my guess -- 1976, when the GE turbo appeared, CHEC excitation appeared... or somewhere right around that.
One further hint - in the large Conrail manual I find a single page GEK-61347 "CHEC" Turbochargers and Magnetic Probes which covers installing the probe and magnets on the turbochargers if used in "CHEC" locomotives, or instructions on using a "CHEC" turbo in a non-CHEC equipped locomotive. The date of this instruction is 12/76 and there appear to be no revisions (indicated on GE pubs by bars on the outside of revised text / illustrations) which might make this the original issue of this notification.
All speculative and circumstantial, but it's the best I have since I can find no GE advertising material announcing CHEC excitation and the turbo speed sensors.
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There's the original post with just a couple edits as I'd constructed it last night. To make it clear - the U33B during the time frame we're talking about here didn't use turbo speed as an input to control (excitation) equipment. Rather, it used intake manifold pressure as an input to governor control equipment; the units also had a fuel limit device interposed in the fuel rack linkage which would act to reduce fuel injection if intake manifold air temperature got too high. (This same device also performed the overspeed shutdown function, with input from an external overspeed governor.)
Will DavisAll right.. you asked for it!
THANK YOU!!!
Thank you, very fascinating.
Interesting! Some details of engine control that almost never get mentioned in the railfan press.
- Erik
Someone just posted on {FORUM NAME REDACTED} in a string about our locomotive blog having been revived that "at least some of Conrail's last order of U23B's had CHEC excitation."
That order was built (as I said over there) in May, 1977. I think these were the last U-series locomotives built. This information merges well with my working assumptions about the introduction of CHEC correlating roughly with introduction of GE turbos.
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