• GE Export Diesels

  • Discussion of General Electric locomotive technology. Current official information can be found here: www.getransportation.com.
Discussion of General Electric locomotive technology. Current official information can be found here: www.getransportation.com.

Moderators: MEC407, AMTK84

  by Allen Hazen
There has been a very interesting (to me, at least!) discussion of GE's early (1950s) export diesels in the "Serial Curiosity" string on this forum. One contributor has suggested we start a new discussion of GE export models; I suggested it might start as a central "bibliography" of sources of information about these locomotives, which have never had much coverage in the North American rail fan press, but which are, so to speak, the ancestral population from which GE's big North American diesels of th 1960s and later evolved.

For a start, here
http://www.locopage.net/ge-history.htm" onclick="window.open(this.href);return false;
is a short history (by Steve Palmano) of GE's (export) U-series diesel locomotives from the 1950s to the 1980s.
  by SSW9389
I agree on several points Allen makes. There is little discussion of these historical GE Universal Series Locomotives. By my count there were roughly 400 Universal Series locomotives built by GE before the XP24 was announced as the U25B. How much experience did GE gain with these early Universal Series units? In my opinion these early GE Universal Series locomotives laid the ground work for the end of Alco.

Ed in Kentucky
  by Allen Hazen
The experience-- and the opportunity to de-bug the C-B engine-- war certainly very valuable to GE when they tried to enter the market for large North American diesels! One of the major reasons railroads were reluctant to try the U25B was that the engine was an un-known quantity to them. GE advertising tried to counter this by emphasizing that the basic engine type hd been in railroad service for years. One GE ad prominently stated that 5,000 cylinders (or maybe 5,000 power assemblies-- I don't have the ad before me, and my memory is hazy about the precise wording) of the C-B engine had been delivered.
With a mix of 8-cylinder and 12-cylinder engines, 400 U-series locomotives doesn't quite get you to 5,000 cylinders, but it is getting into that ball-park. And maybe GE was counting various pre-U applications… maybe even the straight-6 versions of the C-B engine in 70-tonners.

(In the event, the V-16 version of the engine STILL had some de-bugging to do!)
  by SSW9389
Here are some Trains magazine articles mainly concerning the U25B. These articles do not mention any export Universal Series locomotives.

Trains August 1960 presumably written by David P. Morgan. See pages 40-41, the U25B was announced on April 26, 1960.

Trains January 1962 page 32 Annual Motive Power Survey written by David P. Morgan. Note that by late 1961 a total of 20 U25Bs had been sold to three railroads.

Trains September 1962 A Locomotive is Born pages 18-24. The early story of the U25B by David P. Morgan. An a note that 60 U25Bs had been sold so far.

Trains November 1966 Where would dieselization be without GE pages 40-47 by Jerry A. Pinkepank.

Trains August 1982 U25B Biograpy Part 1 by Greg McDonnell pages 42-51. The other diesel that did it.

None of the above articles have very much at all to say about GE export Universal Series locomotives.

Ed in Kentucky
  by Allen Hazen
Those "Trains" articles from the 1960s were a big part of what got me interested in locomotive history! "Trains" had a special GE issue in September 1999 which contains a brief account of GE's locomotive doings from the beginning to the U25B by William D. Middleton (going over much the same ground as the Pinkepank article from 1966): it mentions that some 400 U12 and U18 units had been sold to a wide range of countries by the time the U25B was introduced, but otherwise tells us nothing about them.
  by SSW9389
This website has not been updated since 2008: http://www.locopage.net/ge.htm" onclick="window.open(this.href);return false; It's a start.
  by Allen Hazen
The site SSW9389 links to is very useful: pity it hasn't been updated recently!
Note that the historical essay by Steve Palmano, linked in the first post to this string, is itself linked to this page.
Another useful thing -- the button for it is just below the picture of the U20C a bit below the middle -- is a list of GE export locomotives (including locomotives for Mexico but not those for Canada) from the early 20th C up to 2000. I think (I think I have seen a copy of this list elsewhere on the WWWeb with identification) it is from GE's own sales organization.
It includes model numbers (for units that have model numbers: in other cases sometimes just a brief indication of the general type) and construction (serial) numbers. (Locomotives built by licensees -- including GE do Brasil and Goninans and GE Lokindo, which I think is a joint venture of General Electric and either public or private Indonesian investors -- do NOT have serial numbers in the main GE series... except for a small number of units built by Adtranz in Germany(*).)

(*) The one GE built for Germany is an Adtranz unit: I think it is the "Blue Tiger" demonstrator. The others Adtranz units that I noticed are a small number for Pakistan, whose model number suggests they are derived from the Blue Tiger, but whose engine is listed as an FDL-16 instead of an FDL-12, which makes me want to warn people that even documents originating from GE may contain errors...
  by NorthWest
I second the thanks; it is nice to have a mostly complete listing of all GE export locomotives produced! It would be nice to have an update, as interesting things are happening, including the NEWAG 311D rebuilds.
Allen Hazen wrote: (*) The one GE built for Germany is an Adtranz unit: I think it is the "Blue Tiger" demonstrator. The others Adtranz units that I noticed are a small number for Pakistan, whose model number suggests they are derived from the Blue Tiger, but whose engine is listed as an FDL-16 instead of an FDL-12, which makes me want to warn people that even documents originating from GE may contain errors...
They may well be FDL-16s, as they only have a single cab on what appears to be essentially the same frame as the units built for Europe and Malaysia, but I cannot find a picture clear enough to count hood doors. All online references refer to them as 16 cylinder units.
  by Pneudyne
From the thread “Which Engine Style Looks the Cutest” (http://www.railroad.net/forums/viewtopi ... 20&start=0" onclick="window.open(this.href);return false;) in the "General Discussion: Locomotives, Rolling Stock, and Equipment" forum:
Allen Hazen wrote:Pneudyne--
Re: "taken to the B level" The B level in the evolution of the C-B/GE F series engines is, I think, the mid 1950s version with a nominal output of 150 hp per cylinder. The GE test locomotive set of 1954 (the FA lookalikes that tested on the Erie in Erie colours and were later sold to the Union Pacific) had FVBL-8 in the 1200 hp units and FVBL-12 in the1800 hp units.

So this is the stage of "FDL" evolution that would have gone into early U-series export locomotives, and I think the inline 6 version was used in a U9 model. (But only a few were built before GE switched to Caterpillar engines at that power rating.)

(And, do you think it is PRUDENT to let MEC407 and me know that a V-6 version of the FDL might have been possible after all? Do you REALLY want to encourage out fantasies? (Grin!))
Yes, the “B” version of the C-B engine was the outcome of the co-operative development program between Cooper-Bessemer and GE, and was the variant that was used in the larger models in the Export Universal series from their inception and through to the changeover to the FDL engine in the early 1960s. During that time the 12-cylinder model was changed from having a twin turbocharger installation to a single turbocharger. As far as I know, that was done ahead of the large South African U18C1 order (115 units), which Spoornet documentation shows as having the single-turbocharger version of the engine.

The “B” range included in-line 6 and vee-8, vee-12 and vee-16 versions, although only the vee models were taken into the GE FDL range.

A reasonable inference is that to have included the in-line 6 in the range, GE must have envisaged that it would have reasonable utility, and perhaps that it would be competitive with the Alco 6-251. Given that it could also have chosen the vee-6 model for inclusion in the “B” range, which would have had even greater parts commonality with the other variants, one may impute a definite preference for the in-line 6. Possibly it was seen as a simpler powerplant than the vee-6 for the smaller customers to maintain, and also more competitive with the Alco 6-251. Of course, GE had much experience with the original FW6LT version in the 70-tonner and its derivatives.

Other than the export U9, about which more in a following posting, it is unknown what applications that GE may have envisaged for the FWB6LT engine. An upgrading of the 70-tonner is one possibility. But that continued to use the FWL-6T engine for the remainder of its production run. Its de facto successor was the U6B et seq, but whether that was part of the plan when the export Universals were introduced, or whether it just subsequently happened that way, perhaps because of declining demand for the 70-tonner itself, is unknown. The FWB6LT, slightly derated appears to have been the variant used as the auxiliary powerplant in the UP 8500 hp GTELs. At least its 850 hp rating is well higher than the highest I have seen for the FW6LT, namely 720 hp.

The C-B “B” engine was described in a four-page article in the journal “Diesel Railway Traction” for 1956 November. I have attached the first two pages, with the other two to follow in the next posting.

DRT 195611 p.413.jpg
DRT 195611 p.414.jpg
  by Pneudyne
The other two pages of the C-B engine article.
DRT 195611 p.415.gif
DRT 195611 p.416.jpg
  by Allen Hazen
Thank you, very much! That was a very interesting article.
The engine configuration with two turbochargers at opposite ends is very unusual in American locomotive practice-- I have seen references to arrangements like it in engines built by non-U.S. engine manufacturers, but I don't know of any American locomotives (other than those mentioned in the next paragraph!) with engines so configured: GE had gone to the more common one turbocharger arrangement by the time the U25B was introduced. The HDL engine used on the AC60CW had two turbochargers, but they were mounted side-by-side at the same end of the engine (the end opposite the generator).
From the dates, one would suspect that GE's earliest North American units with … the C-B engine described -- would have had this arrangement. I wish I had overhead photos of the GE test locomotive 750, or of a UD18B! Still, what I DO have…
There is a scale drawing of one of the units of 750 (by Julian Cavalier) in the February 1972 issue of "Railroad Model Craftsman". Side view, but it seems to show two exhaust stacks, one at each end of the engine compartment, as expected. (I've looked at it many times, but didn't notice this feature until now!) As for the UD18B… There is aside-view photograph in "Diesel Locomotives: the first fifty years." It shows SOMETHING projecting up from the long hood roof at each end of the engine, but the two don't look quite the same: the one at the rear (where one expects exhaust stacks on Alco and GE units) looks like an exhaust stack, but the forward one seems narrower.
  by Pneudyne
Regarding the GE U9 export model, 990/900 hp and powered by the C-B FWB6LT engine, I suppose that in hindsight it was something of an oddity, but that when the Export Universal range was planned, it seemed reasonable to include a fully-fledged road-switcher in the 900 to 1000 hp range. For example EMD had included the G8 model, 950/875 hp road-switcher in its standard export range from circa 1954. In the event, the market for that type of locomotive seemed to peter out after 1960 or so, and GE obtained but a small share of what there was, with 29 total, comprised of 13 U9B and 16 U9C.

The U9 was based upon the same frame as the FVBL8T-powered 1320/1200 hp U12, so shared the same basic dimensions. It had the GT599 main generator instead of the GT581 used on the U12, but retained the triplex auxiliary gear drive system. Generally it was homologous with the U12 and the larger U18 in terms of its control system and features and facilities. On a basic weight basis, it was around 8 000 lb lighter than the U12, so it did not offer major relief in the axle loading department. That it shared a frame with the U12 likely made it heavier and possibly longer than it otherwise might have been, but presumably there was a production cost benefit to GE that gave it more flexibility with both U9 and U12 pricing. By the way, I know very little about the GT599 main generator. It should not surprise me if it shared the same frame size as the GT584, but that is pure speculation.

Anyway, EMD had set a precedent, in that its G8 shared the same frame as the 1425/1310 hp G12. Power-wise, the G8 was two-thirds of a G12, whereas the U9 was three quarters of a U12. And the shared frame probably made the G8 heavyish for its power. I understand that EMD’s original plan included a G6, powered by the 6-567 engine and on the same frame, but perhaps wisely, that idea was not brought to fruition.

In offering both B-B (U9B) and C-C (U9C) variants, GE had stepped ahead of EMD, who offered only 4-motor B-B and A1A-A1A variants of the G8. Whilst GE did not offer A1A-A1A versions of any of the Universals, and at the time was on record as being antithetical to this wheel arrangement, it probably would have built such had any customer asked for it.

GE had announced its export Universal range in the early part of 1956. In the latter part of 1956, Alco announced an extended export model range that included the DL531, of 975/900 hp. This was a light, low-profile road-switcher powered by the 6-251 engine, with GE GT584 main generator and GE761 (or GE764) traction motors. It was available with B-B, C-C and A1A-A1A wheel arrangements, although the last-mentioned was never built. Being designed around the 6-251 engine, the DL531 was noticeably shorter and lighter than the GE U9, with which it directly competed. It was also somewhat simpler. It had a belt-driven exciter/auxiliary generator that was usually associated with the lower end of the power range, although it did have full (Lemp 1914) load control via a Woodward PG governor with integral load control rheostat. It had trimount trucks, probably adequate for its typically realizable operating speeds, whereas the GE U9, like the U12 and U18, had floating bolster trucks. The Alco DL531 might have had a production cost advantage over the GE U9, and I should not be surprised if Alco was aggressive in its pricing. As it did not have a “horse” in the U12 class, it was probably eager for all for the DL531 business it could get. Alco could claim some electrical parts commonality with the GE Universals, so that for example the DL531 would not be out-of-place in a fleet which also included for example U12 and U18 models. But commonality might not have been such a big issue for the target customers, amongst whom the Argentinean and Brasilian state railroads at the time were inclined to spread their business around. A significant early order for the DL531 was that from RFFSA Brasil, who acquired 77, of which 57 were C-C and 20 were B-B. In the same period RFFSA acquired from GE 3 U9B, 52 U12B and 12 U12C.

Anyway, one might say that the DL531 was less compromised than the GE U9 and EMD G8, and it obtained a goodly share of the business on offer through to about 1960, after which the landscape had changed.

GE’s initial Universal range included the small and simple end-cab U4B and U6B models, both B-B only, and with the choice of industrial switcher rigid bolster or floating bolster road trucks. These had Caterpillar engines, GT601 main generators with belt-driven exciter/auxiliary generator and GE761 or GE764 motors. They had simple “inherent characteristic” load control (Lemp 1924), and the engines had Caterpillar governors controlled by an electropneumatic throttle operator. The U4B was never built, and the U6B had a slowish start, but it almost inevitably just a matter of time before the customary power growth moved this design towards 1000 hp, where it would offer a credible alternative to the fully-fledged road-switcher. This part of GE’s Universal range was a logical development of the previous Caterpillar-powered 50, 52 and 54-ton range. The 50-tonner had originated as something of a “smaller brother” to the 70-tonner, and the production of the 50- and 52-ton models continued into the Universal era.

EMD had likely seen the coming trend, and in 1958 released both the GL8 and GA8. Both of these were end-cab models powered by the 8-567 engine, and were shorter and lighter than the G8. The GA8 was the “super-simple” version, B-B with cardan shaft drive and freight-car style trucks. The GL8 was of normal configuration, originally available only in B-B form, although an A1A-A1A variant (in two versions) was soon added. The GL8 did not directly supersede the G8, but once it was in production virtually eliminated sales of the latter except in Australasia. With these models EMD was able to offer some competition for the GE end-cab models, and also extend upwards the power range covered by this kind of locomotive.

Alco in 1961 introduced its 1350/1200 hp DL535, essentially a longer and heavier version of the DL531 C-C variant with an uprated 6-251 engine and GE GT581 main generator, although retaining the belt-driven exciter/auxiliary generator. Alco’s primary objective seems to have been to offer a locomotive that was or could be seen as being proximate to the GE U13 and EMD G12. The DL535 was slightly shorter than the GE U13C, and its base weight was somewhat lower. Alco also may have realized also that the 900-1000 hp bracket was now largely the province of the end-cab unit rather than the road-switcher, and so would have seen the upgrade as pivotal in maintaining its 6-cylinder sales. And in fact, once the DL-535 was available, sales of the DL-531 fell away except in Australia. Whilst the DL-535 may have cannibalized some potential DL-531 sales, it does look as if the market for 900-1000 hp road switchers had largely dried up. As at the time Alco did not have a vee-8 version of its 251 engine, it was obliged to uprate its 6-251. Its resultant seriously high (for the time) mean effective pressure seemed not to be a problem nor did it deter customers.

Against that background, 20/20 hindsight shows that the U9 probably had little chance of selling in quantity. Still, GE kept the model in its range through its power restating exercise circa 1961, whereupon the U9B and U9C became the U10B and U10C respectively, of 1090/1000 hp. But none were built. By then the U6B had been superseded by the U8B, at 900/810 hp, which was fitted with the Caterpillar D398 engine in place of the D397. In the power restating, the U12B/C had become the U13B/C, and the U18C had become the U20C. I suspect that the U10B/C was deleted from the catalogue during 1962. By mid-1962, a more powerful version of the U8B end-cab model had been added as the UM10B. This had an uprated Caterpillar D398 engine, set at 1050/950 hp. Possibly the UM10B designation was used to distinguish this new model from the never-built 6-cylinder U10B. Anyway, after a short interval, the UM10B was renamed as the U10B.

So, the 900 to 1000 hp category was now dominated by the simple end-cab locomotive. That said, the GE UM10B/U10B could be optioned up, with road trucks, MU equipment and dynamic brakes if required. Modest HEP (in the vicinity of 10 to 15 kW), for train lighting, was an option, as on the larger models.

In the mid-1960s though GE did build, as a UM10B variant, a road-switcher version of the U10B for RENFE Spain, and again in the 1970s for OSE Greece. This had an extended frame and a high short hood to accommodate a train heating boiler. This might have been envisaged when the original UM10B was designed. A 1962 September “Diesel Railway Traction” article noted that the train heating boiler was optional on the UM10B and upwards. The U13B/C and U20C had room in the carbody for the boiler, but the basic UM10B did not. Whether the U9B/C and not-built U10B/C had room for a boiler is unknown. Conceivably the 6-cylinder engine, being longer than the vee-8, encroached upon the space set aside for it. By way of comparison, the Alco DL535 required a four-foot frame extension to accommodate a train heating boiler, and this variant was built for RENFE Spain as the DL535S and for OSE Greece as the DL537.

Also, in the 1970s GE built the U10A1A for Hedjaz Jordan. This had an extended frame to accommodate the A1A trucks, and was of road-switcher form with the short, low nose that I think was first seen on the U26C. So even though the end-cab form dominated, there were still some-road switchers required here and there.

Inevitably, as part of the scene-setting, this posting has required mention of competing Alco and EMD models, particularly the Alco 6-cylinder locomotives, as these were the most comparable to the GE U9. To complete the worldwide competitive picture, pertinent non-US locomotives in the subject power class might also be considered, particularly those from Alsthom and English Electric. But I don’t think that would add materially to the piece.

  by Pneudyne
Allen Hazen wrote: From the dates, one would suspect that GE's earliest North American units with … the C-B engine described -- would have had this arrangement. I wish I had overhead photos of the GE test locomotive 750, or of a UD18B!.
Agreed. The Mexican UD18B fleet was the first series production that included the C-B FVBL12T engine. It preceded the initial U18C fleets built for Argentina, Turkey and Brasil, all of which I understand had the twin-turbo version of the engine, although I do not have hard confirmation. These deliveries were completed by early 1958. The single-turbo engine then first appeared on the South African U18C1 fleet, deliveries of which started in 1959 September. Even there, anecdotal information suggests that a small number of the early deliveries had the twin-turbo engine.

Thus the best interpretation of the evidence is that the change from the twin to the single turbo layout took place during 1959, possibly with no production overlap.

Regarding #750, my understanding is that as built, the A-units had the FVBL8T engine, and the B-units had the FVBL12T engine. Logically that would have been the twin-turbo version, as it does not look as if the single-turbo version of the FVB engine had been developed at that stage.

The rebuilding to UM20 standard happened in 1959, as I recall. As the cab units received new FVBL12T engines, the chances are that they would have been of the single-turbo type. Whether the booster unit engines were replaced with or rebuilt as single-turbo engines is I think anyone’s guess.

I am not sure if the UM20 designation was applied at the time of rebuilding or later. But note that the designation is based upon the restated power output, and that for the export models. This change seems to have happened in 1961, e.g. the U18C became the U20C.

The Kratville UP Motive Power Plan Package book included a diagram of an A-unit in UP guise. The broken line depiction of the engine clearly showed that it was a single-turbo unit. But there were two apparent exhaust outlets, the rear one actually used and the forward one seemingly unused. It was in about the right position for a twin-turbo 12-cylinder engine. It would not have been needed for the originally installed 8-cylinder engine, but then it is likely that the A-units, like the B-units, were designed to accommodate the 12-cylinder engine, but initially fitted with 8-cylinder engines because GE wanted to road-test both versions.

BUT.....we cannot completely outrule the possibility of their having been a single-turbo version FVBL12T earlier than 1959.

GE had used the earlier C-B FVL12T engine in the Argentinean (and Chilean) shovel-nose type exports, and in the Queensland Railways (QR) road-switchers that ultimately became the QR 1150 class. The engines in the Argentinean units had two turbochargers, one at each end. But the QR 1150 engines had single turbochargers. From what I have seen, the twin turbo installation was the C-B norm for industrial and other applications. Quite possibly the engineering work that was done to produce a single-turbo FVL12T for QR was reasonably transferable to the FVBL12T, which would have made an early version so equipped not so unlikely.

  by Allen Hazen
Many thanks! It will take a while to digest all that information: maybe (and maybe not) I'll have something to add or comment later!
Just to complicate things… Other sources indicate that of the four unit 750 test locomotive, one A and one B unit had 12 cylinder engines, and the other A and B units had 8 cylinders. (Oe of the 8 cylinder engines from this set has apparently been preserved at a railroad museum in North East Pennsylvania (near Erie).

I think -- the board moderator, I guess, makes the final call, but my recommendation would be -- that mention of locomotive types from Brand X and Brand Y are appropriate to this forum in this context: indicating just what some GE models were competing with or were intended to compete with. Certainly the story is much more informative when this information is included!
  by Pneudyne
Allen Hazen wrote:Just to complicate things… Other sources indicate that of the four unit 750 test locomotive, one A and one B unit had 12 cylinder engines, and the other A and B units had 8 cylinders. (Oe of the 8 cylinder engines from this set has apparently been preserved at a railroad museum in North East Pennsylvania (near Erie).
I probably got that wrong, as I was relying on memory. Now though, I cannot put my hands on a dependable reference.
Pneudyne wrote: By the way, I know very little about the GT599 main generator. It should not surprise me if it shared the same frame size as the GT584, but that is pure speculation.
Perhaps not. The GT599A1 was definitely designed for the 900 hp U9. Thus I should have expected it to be similar in frame size to the GT584, which was apparently designed for use with the Alco 6-251 engine of similar size, rotational speed and power output.

But in fact the GT584 has a somewhat different history. It was originally designed for use in 800 hp and 1200 hp yard switchers, GT584A1 prototype and GT584D1 production model. The GT584D3 was tailored for the 900 hp requirement, which although not specifically called-out in the available GE data, very likely referred to the Alco 6-251 engine as used in the DL531.

There was also a GT584E1 variant designed to fit the Cooper-Bessemer engine and listed as a special for Manila Railways (MRR). That means it was used in the MRR streamliners and modified road switchers fitted with the C-B 8-cylinder engine, and quoted as being 1320/1200 hp.

So if the GT584 was big enough to handle 1200 hp, it is possible that the GT599 might actually have been a bit smaller, perhaps optimized for the C-B 6-cylinder engine. But then one might ask why did Alco not use a suitable variant of the GT599 for its lightweight DL531, if that would have saved some weight. So how the GT599 related to the GT584 remains an open question.

Still, the GT584 might have been stretched a bit at 1200 hp, with no room for developmental power increases. For its production U12 with the 8-cylinder C-B engine, GE chose the larger GT581, as did Alco for its DL535 with its uprated 6-cylinder engine.

Interesting is that the traction motor groupings for the Alco DL531 were 3S2P and 2S3P, rather than the more common 2S3P and 6P. That suggests that the GT584, or at least the GT584D3 variant, did not have enough current capacity to feed six GE761 motors in 6P. Traction motor groupings for the MRR units are unknown. GE had previously used 3S2P/2S3P combination for the Queensland Railways road switchers, so may have repeated that for MRR.

The C-B 6-cylinder auxiliary powerplants in the UP 8500 hp GTELs had the GT597A1 generator. I am not sure that I have seen any information as to how this was connected to the traction motors for hostling operations – I’ll need to check.

The first order for the U9 was placed by Chilean State Railways. It called for 11 of the U9C variety, for use on its northern metre gauge lines. This was part of a larger order that might be described as “something old, something new”. The two other items were repeats of earlier broad gauge designs for the southern network, namely 5 of the 1750/1600 hp C-C shovel-nose cab units and 15 B-B 70-tonners.

So that was quite a mix of equipment and details. The shovel-nose units had Alco 12-244H engines, GT581A1 main generators, GE731 motors and Amplidyne control systems with the 17MG6 governor. The 70-tonners had C-B FWL6T engines set at 720/660 hp, GT571C3 generators, and GE761 motors (whereas the earlier batch had had GE748 motors). They had the customary Woodward UG8 governors and one assumes the customary inherent characteristic load control. And as they were MU-equipped, then 7-notch electric throttles would have been normal. But as some export 70-tonners were fitted with 7-notch MU air throttles (similar to those used on the US Gypsum 54-tonners), that possibility cannot be outruled. The U9C fleet had C-B FWBL6T engines, GT599A1 generators, GE761 motors and Woodward PG governors with integral load control rheostats.

Following the U9C fleet, for its northern metre gauge lines Chilean State Railways then moved up the power scale, next acquiring 4 GE U12C. These were closely followed by 19 Alco DL535 and 19 EMD GR12U, so all three contenders of the time in the 1200 to 1300 hp class were represented. Then it later on it returned to GE for 8 U13C.

This progression might be taken as an indicator that the 1200 to 1300 hp road switcher had greater utility than the 900 to 1000 hp category. Also, the U9C order might have reflected a familiarity with the C-B 6-cylinder engine. As well as earlier the earlier broad-gauge B-B 70-tonners, Chilean State Railways also had a fleet of 30 of the metre-gauge C+C version.