GG-1and MU operation

Does anyone know if the GG-1 could be put into multiple unit operation ala the AEM-7? Thank you all in advance!

Ryand-Smith wrote:Does anyone know if the GG-1 could be put into multiple unit operation ala the AEM-7? Thank you all in advance!

Yes. It was fairly common in freight service. Even Amtrak did it at least once: http://www.rrpicturearchives.net/showPi ... id=2012241" onclick="window.open(this.href);return false;

chrisf wrote:

Ryand-Smith wrote:Does anyone know if the GG-1 could be put into multiple unit operation ala the AEM-7? Thank you all in advance!

Yes. It was fairly common in freight service.

Thank you. I have seen pictures of GG-1s in the final black paint scheme pulling freight and running on the North Jersey line, but I was not sure if they could be MUd. Thank you again.

While we're at it… Could the GG-1operate in multiple with any other type of locomotive? I'm inclined to doubt it: the idea of multiple-unit "lash-ups" of different locomotive types wasn't on PRR's mental map when the GG-1 was defined, and PRR electric locomotives had restricted multiple-unit capabilities. (Ex: I think I've read that the E44 could operate in multiple with at least some diesels, but only as lead unit: The E44's electrical system wasn't set up to "take orders from" a diesel.) But does anyone here know for sure?

The PRR E2b prototypes were equipped to operate in MU with the older P5 fleet. That is probably why they had 32-volt rather than 74-volt auxiliary electrical systems. There is credible confirmation in a book, including a picture of the E2b MU sockets with appropriate labels, but I cannot find my copy right now.

The GG1 MU capability I do not know about.

I have read - on the forums I think - that some of the E44 fleet were retrofitted to work in MU with trailing diesels, but I have not been able to find any authoritative confirmation that this was so, and if it was, the details of how it was done. One of the potential issues is that with a manually accelerated high-power electric locomotive, the engineer may well still be notching up at 30 mile/h and above, whereas the trailing diesels are probably advantageously gotten into notch 8 by about 15 mile/h. Not a deal breaker, but it would appear to require careful mapping from the electric to the many fewer diesel notches. (A similar issue would have arisen with the UP GTELs when they were retrofitted to MU with trailing diesels, but the details of that system remain stubbornly hidden.)

For electric power units to be controlled by diesels, I think that there would need to be at least partial automatic acceleration. In this regard, the New Haven FL9, in electric mode, was controlled in 8 steps by the diesel throttle, but between some of the diesel notches there were several electric notches under automatic acceleration control.

The only case I know of where electric locomotives could be controlled by leading diesel locomotives was in the UK. The BR 33/1 class diesels could control trailing 73/1 class electrodiesels, including selecting whether the latter operated in electric or diesel mode. This was because both classes were equipped with 4-notch EMU-type control systems as well as their respective own underlying control systems (two, one each for diesel and electric in the 73/1 case). Both could also MU with many of the BR Southern Region (SR) EMU consists. The BRSR first generation DEMUs were nearly brought into this group, and BR’s class 210 second-generation DEMU prototype was equipped to work with EMUs of its own generation.

There may well be other examples of diesels controlling electrics in Europe. With the advent of electronics, heterogeneous MU would have become a lot easier.

Ideally I suppose, one would want a control system that maximized electric locomotive output in a given situation, and used the diesels as supplementary tractive effort and power only to the extent needed.

Somewhere I have seen it said that the VGN E33Cs could MU with the EL2Bs. That seems unlikely, particularly in respect of electric braking. So that’s very much a maybe that definitely needs authentication.


Cheers,

The comments on the PRR E44 and VGN E33 MU capabilities were provided by Cunningham in his book about the New Haven EP-5.

The P5 was I think covered in Solomon’s book on electric locomotives.


Holley provided some information on the Milwaukee mixed MU case:

And the FL9 control details were in Sinopec and May’s book on that class.


Cheers,

Pneudyne wrote:And the FL9 control details were in Sinopec and May’s book on that class.

That should have been Snopek and LaMay. Here is the page showing the FL9 throttle sequence during electric operation.
Cheers,

Pneudyne-- Thank you, once again, for the very informative posts, and the scans of source material!

Re: the PRR/GE E44: There is an operator's manual for this tip on George Elwood's "Fallen Flags" rail image site. The two pages on multiple-unit operation don't say anything about "mix or match," but the wording suggests to me that only m.u. with other E44 was envisioned. However, the introduction to the electric locomotive section of Alvin Stauffer and Bert Pennypacker, "Pennsy Power II"
(1968) says "Another feature of the E-44 permits its multiple-unit hookup with diesels, but the electric must be the lead,or controlling engine." I don't think I've ever seen a photograph of an E44 in m.u. with a diesel: I will post a question to the Pennsylvania Railroad forum to ask if this theoretical capability was ever actually utilized.

Re: the CMStP&P's homemade e-to-d m.u. equipment… Given the differences between electric and diesel control systems you mention in your first post to this topic, it's obviously not a trivial problem, but clearly a competent electrical engineer would be able to design equipment allowing an electric locomotive to "impersonate" a diesel for the purpose of ordering other diesels around. A similar bit of ingenuity was reported in an old (1970s?) "Trains" magazine article. The Clinchfield Railroad had an ancient 4-6-0 steam locomotive which they used on an annual Christmas train (Santa Clause on the observation platform of the last car would give out toys to children in on-line villages). The steam locomotive was too small to pull a modern train over the mountains (and maybe old and delicate enough that they really didn't want to make it try), so it was coupled to a diesel (I think usually an F-unit cabless booster-- surely aesthetically the least obtrusive diesel possible!) behind its tender. The diesel being controlled through its normal m.u. system, the m.u. "commands" being generated by apparatus, designed and built in Clinchfield shops, linked to the steam locomotive's throttle.

Another did-bit from "Pennsy Power II": the PRR/GE E-2b locomotives may not have been m.u. compatible with the P5a as built: a picture caption on p. 157 says they "were later changed to MU with the P-5a's."

I didn’t think to look in the Staufer books – one tends to view then as a tertiary source – but they nevertheless do sometimes provide additional information.

The E2b and P5A case is an interesting one. Here is a pertinent picture from Solomon, “Electric Locomotives”:
It shows the E2B as having four MU sockets on each side, the outermost being marked “P5A” only. This picture could have been taken at any time in the operating history of the E2b fleet, so did not necessarily reflect its original configuration.

But here is a page from the Railway Gazette 1952 April 18 article on the E2b. It is highly probable that the picture shows the locomotive pair in “as built” condition. The same array of four MU sockets per side is visible, although their labelling is not. I think that that points to P5A MU capability being an original feature.

Whilst retrofitting was certainly not impossible, factoring in mixed MU at the design stage would have been easier. Thus the new locomotive design could have been configured with the same number of accelerating notches as the older design, and with the same auxiliary electrical system voltage. And as said, it would be difficult to rationalize the 32-volt choice in an era when 74 volts was the norm other than that it was for backward compatibility.

So I’d say that the preponderance of evidence supports the notion that the E2b could MU with the P5A as built.

Re the E44, it was the lack of mention of diesel MU capability in the Operating Manual that made me rather sceptical. Given that the OM was railroad-specific, it is not as if it was restricted to covering the basic model only. But then it was numbered GEJ-3809B, and covered both the ignitron and silicon rectifier builds. That suggests that there was at least one earlier issue. Just possibly diesel MU capability was an original feature on some of the earlier build, but discontinued and possibly removed before the last of the fleet were built, and so not included in the late edition of the OM.

On the steam-to-diesel MU case, as I recall the 1970s operators of ex-SP #4449 had a portable diesel controller that was used for that purpose, and I think that they claimed to be the first to do this . And in Victoria, Australia, one of the R-class 4-6-4 locomotives in preservation was fitted with a diesel control stand. This combination appears to have been a preservation-era development. Westinghouse is reputed to have developed MU systems for steam locomotives, although evidently never deployed. The closest approach to steam MU was probably found in European push-pull passenger train operations, where a trailing steam locomotive (mid-train or at the rear) was controlled from a leading cab-car.


Cheers,

Allen Hazen wrote:Pneudyne-- Thank you, once again, for the very informative posts, and the scans of source material!
A similar bit of ingenuity was reported in an old (1970s?) "Trains" magazine article. The Clinchfield Railroad had an ancient 4-6-0 steam locomotive which they used on an annual Christmas train (Santa Clause on the observation platform of the last car would give out toys to children in on-line villages). The steam locomotive was too small to pull a modern train over the mountains (and maybe old and delicate enough that they really didn't want to make it try), so it was coupled to a diesel (I think usually an F-unit cabless booster-- surely aesthetically the least obtrusive diesel possible!) behind its tender. The diesel being controlled through its normal m.u. system, the m.u. "commands" being generated by apparatus, designed and built in Clinchfield shops, linked to the steam locomotive's throttle.

The system is now at the B&O museum, and still has the anachronistic looking MU box in the cab.

Just to deepen the E-2b mystery…
--The Westinghouse rectifier prototypes built at the same time (E-2c and E-3b) also seem to have four sockets on either side of the pilot, and I've never seen any suggestion that they were capable of m.u. with P5a.
--A number of photos of E-2b seem to show the outermost socket (the one stencilled "P5a only" in the photograph from Solomon) removed, and its location plated over. Including photographs showing the E-2b coupled to a P5a.
--As a further complication, there were two "batches" of E-2b: the four units (4939-4941) originally built for PRR and the two (PRR numbers 4942-4943) sent to the Great Northern and subsequently acquired by the PRR. Perhaps the ones built for PRR were could m.u. with P5a as built, and the other two were modified after they went to PRR? (Aside: it seems that only the Great Northern units had the small central number box over the headlight-- useful in identifying which batch an E2b belongs to in a photo in which the number isn't visible.)

Scratchy: thanks for note. In the 1970s the idea that the B&O and the Clinchfield would end up parts of the same system might have seemed strange!

Configuring the E2c and E3b rectifier locomotives to be MU compatible with the P5A was probably an order of magnitude more difficult than doing the same for the E2b, and without precedent, so I imagine that if it were considered at all, it was soon put in the “too hard” basket. In the E2b case, it was really just a question of detail. Presumably the 21-notch control, as used on the P5A, was found to be not inimical to achieving the desired performance for the E2b, so was acceptable.

Re the GG1, the single-source of information that I can find indicates that it had 66-notch control. In turn that suggests that it might have had the facility of two intermediate notches between the main notches as was found on the later New Haven electric locomotives, as described here:
Incorporating trailing diesel MU capability in the E44 – if in fact it was done - was probably of intermediate complexity There was the precedent of the Milwaukee’s in-house work, and also that of the UP GTEL case, where 20 control notches were mapped back to 8, and where I suspect that the issue of different notching vs. speed curves through to full power also applied.


Cheers,

Re the E44, none of the pictures that I can find on the web show other than the standard arrangement of two MU jumper sockets each side, sometimes with dummy receptacles (one each side) mounted well above and often with jumper cables in place. For controlling trailing diesels, one would expect to see another MU jumper socket, and perhaps a field-loop dynamic brake socket as well. Their apparent absence, coupled with no mention in the operating manual, reinforces the suspicion that the alleged diesel MU capability may have been more myth than fact. Also, would the Pennsy have had a material operational need for mixed MU operations over its electrified sections?


Cheers,

Pure speculation here, maybe the reason E44's had to lead is most likely that there were no diesels equipped with pantograph control. I.E, the ability to raise and lower the pantograph(s)
on trailing electric units.