I run a variety of 1st and 2nd generation locomotives. EMD, and Alco mostly but a few GE and maybe an upcoming Baldwin project. Were they compatible in M.U. arrangements? Or were they ever converted to do so? Thanks. Dan
Yes, they all Mu'd together. Originally only Baldwin locomotives would not MU with locomotives of other manufacturers due to the fact that they used a different MU method. Railroads changed them so they could MU with any other manufacturers locomotives.
Not on the STRATTON & GILLETTE system!
.
I won't even couple an F7B to an F3A!
Someone else will need to give you the answer. I honestly do not know when it comes to early diesels. I know that GP-7s were coupled to F cab units as booseters out west, but is that as early as you are asking about?
-Kevin
Living the dream.
I'm talking about running EMD F 7s, GP 7, 9s GP 35, SD 9, Alco RS 1, RS 3, RSD 4-5, maybe a Baldwin Shark .
Baldwins were pretty much the only ones that wouldn't MU with the rest. Some railroads later rebuilt them to work with the rest.
Why wouldn't you MU an F3 and F7? That was quite common.
My club train runs with a Trainmaster sandwiched by a pair of GP-7's. This is based on an actual MU configuration, where I'm told the crew would contrive to make sure the front and rear locos were the GP-7's so they didn't have to ride in the Trainmaster due to its much rougher ride.
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
Most locomotives with standard 27-pin electric MU would run under control. The Shark is an exception: it used a 'stepless' air throttle and to my knowledge none of them were converted to 8-notch compatibility except the 3 PRR Alco conversions (which wound up being almost pure Alco above the deck).
Two concerns: units with different gearing might not do well together, and units from different manufacturers might take different times to load meaning that one might nuzzle up to or bang against another in coming up to speed (I remember at least one account of this in Trains).
There are some truly remarkable consists to be seen on the Web ('dog's breakfast' sometimes used in the caption). Don't forget FMs; they MU too.
Whatever got the required horsepower for the train to be hauled.
There's a video on Youtube I've seen that shows the loading issue can be a problem even in modern locos. EMDs with their 2 stroke prime movers have always been fairly quick to load, GEs with their 4 stroke motors are slower.
The subject was covered by an article by Jerry Pinkepank on Page 45 of the December 1968 issue of Trains Magazine.
It suggests that most types could operate in MU after about 1958. General Electric could always MU with Alco and EMD, although early GEs had sixteen throttle notches compared to eight for the others.
The 27 point jumper cable was not always used but became standard by the early 1960s although Union Pacif used an early two cable system originated by Alco up until 1966 at least. Modified and adapter cables could be used between locomotives with mismatched MU sockets.
However, the article notes that Alco switchers and RS-1s used a non-standard system that used only three wires for throttle control rather than the standard four, so modifying the jumpers wouldn't help.
Peter
SeeYou190 know that GP-7s were coupled to F cab units as booseters out west, but is that as early as you are asking about?
The SOO Line did this too.
Mike.
My You Tube
The loading-speed issue has nothing to do with 2-stroke vs. 4-stroke; it's electrical, and later, computer-related. There are valid pollution-control-related reasons to control loading, too.
It is true in a sense that EMD's superturbocharger allows quicker engine acceleration into a load, because it provides force-induced proportional combustion air without suffering that 'Alco syndrome' caused by one big turbo driven off long manifolds. But that has little to do with the engine itself. A solution would be to adapt an air starter and overrunning sprag clutch to the turbo and arrange to spin up the wheel ... and wake up the neighborhood! ... and of course the patent notes are full of electric methods of getting the same effect.
A definitive cure for 'Alco syndrome' is to unload the Diesel engine electrically as it comes up to speed. This spools up the turbo with minimal rack, before significant sustained overfueling effects occur, then you load smoothly and progressively following the best load curve for the engine. I understand that this is part of at least some of the GE slow-loading approach, as a C-B or FDL will smoke at least as bad as a 244/251 when there is turbo lag for any reason.
It was fun to watch U34CH's on EL. This was about the only place you could see a big GE (these were essentially U36s with HEP tapped from the main generator) accelerated hard with a lightweight load on the drawbar, and these were set up to load pretty quick, as the overfueling in the first few seconds manifested as orange laminar flame and not black smoke, and the HEP setup held the prime mover at some percentage off idle with the train stopped.
I would add to what Peter Clark said, not by way of correction, that some roads used nonstandard pinout in the 27-pin cables. For some reason I remember L&N and GM&O in this connection (pun ruefully acknowledged). There could be strange consequences if you innocently lashed incompatible units together (not that there was too much likelihood, in that era, of that occurring).
Some early Alco switchers had air throttles but I don't think these were set up to MU with each other; this would be incompatible with the Baldwin-Westinghouse system.
It would be rare to see switchers active in a consist of road units, but roads like PC sure did it -- not with earlier Alcos, for the reason given -- and one railroad (LV) famously used MUed sets of up to five of what they called 'pups' to do fairly heavy work. So it may pay to know what would and wouldn't work prototypically, even if only to gin up a good cover story for rivet-counting wisenheimers.
Even what you said shows how it is, at least more than a little, a 2 stroke vs 4 stroke difference. A 2 stroke ANYTHING with be able to reach its power band under load faster than a 4 stroke. Those GEs loaded fast because the never were down on the low part of their power curve when stopped because the HEP kept the prime mover off idle. Like any internal combustion engine, there's a torque curve and peak torque is never going ot be at idle. The faster the engine can get to peak, or at least up in the fat part of the toque curve, the faster it will be able to provide the power to the generator/alternator that is required. The main difference in the switch gear is so that it doesn't place such a load on the generator that would overload the prime mover. Similar to dropping the clutch without revving the engine enough, but not exactly because there is indeed some elasticity in the system because the transmission is electrical rather than mechanical and there is the whole reactive component. The rate at with the controller can control power delivery to the traction motors is governed by how fast the prime mover can ramp up the power delivery to the generator. There is also the factor of how much current the tractioon motors can handle, as well as the contactors and all that, which additional limits how fast power can be applied, and the total tractive effort so you don't just spin the wheels, but even if you could put down infinite power and switch infinite power, the limiting factor would be how fast the prime mover can make that power.
rrinkerA 2 stroke ANYTHING with be able to reach its power band under load faster than a 4 stroke.
Look more carefully -- much more carefully -- at the effective torque rise between, say, a 567D and one of the contemporary four-strokes. There is a slight nominal advantage for the number of power strokes per revolution but that is partially overcome by the higher combustion efficiency and sustained effective pressure in the absence of scavenging. Note also the fixed parasitic drain of the Roots blower on a NA GM engine, which does not affect steady-state power nearly as much as angular acceleration (I know we are discussing turbos, but the EMD drive up to at least notch 4 has similar crank drag).
Even if a good four-stroke requires additional fuel during rotational acceleration, you will note this is only a transient increase of sfc over what the GM 2-stroke equivalent is, with the difference likely made up in spades by the more efficient operation once at steady-state power (particularly in Run 8).
Baldwins were fun-loading for a reason other than 370F motors; the idle on a 600-series could and did produce enough torque at the main generator to get the engine to a balancing speed in the mid-twenties mph. (There's at least one video of this on YouTube, I think at Portola). This made up in some part for the much higher rotational inertia of that enormous crank and reciprocating parts when the air throttle was opened quickly.
There is a case of one manufacturer's locomotives not MUing with each other. Around 1950 New Haven bought ten Fairbanks-Morse Loewy styled H-16-44s. In 1956 the NH went back to F-M for 15 of their later Trainmaster styled H-16-44s, numbered 1600-1614. Both groups were geared for 80 mph and had steam generators for use in passenger service. The earlier 590-599 series had air throttles and couldn't MU with anything except each other while, the 1600-1614 had electric throttles because they were bought to be compatible and MU with the 30 GP-9s and 15 RS-11s purchased along with them in 1956. This is in light of the fact NH had bought ten F-M C-24-5 passenger units at about the same time as the 590s. These 2400 hp cab units frequently MUed with NH's 27 ALCo PA-1s, which had electrical MU control! Another interesting aspect of NH's early dieselization involves their ALCo FA-/FB-1s. In 1947 NH bought 30 FA-1s and 15 FB-1s to make 15 A-B-A sets to eliminate steam on their mountainous Maybrook line. They quickly found out that the 4500hp was insufficient and, went back to ALCo for five more FB-1s to make five A-B-B-A sets with 6000 hp. By this time the FA/FB-1 had been superceded in ALCo's catalog by the 1600 hp FA-/FB-2. NH took five FB-2s and built their A-B-B-A sets. This gave them the distinction of owning FB-2s but, no A units. At the same time they also rostered 45 1600 hp RS-3s. People ask why didn't they just plug an RS-3 into their FA/FB consist instead of buying additional B units. The answer as explained to me was, the FA/FBs were geared for a maximum speed of 65 mph while the RS-3s were geared for 80 mph as borne out by the employes timetables. The covered wagons could operate longer at lower speeds encountered on the Maybrook. A higher geared unit would get into serious trouble if MUed with the cabs so when MUing a power set, gearing is also an issue because in addition to maximum speed allowed, it also affects "minimum continuous speed" as well. IN drag service, the highest MCS governs the consist. That is why you rarely saw passenger units MIXED with freight units on freight trains. This is not to say that passenger units never pulled freight, they just did it in matched consist of similar gearing and MCS. MCS was also known as "short term rating" or in most cases, the maximum amperage that could be passed through the traction motors for 15 minutes. Exceeding this rating would result in heat damaging the motors. This was also a factor leading to the SD, RSD, and other six motor units. Not only did the additional motors increase the adhesion, and weight distribution, they also lowered the amperage required to move the train at lower speeds. Thus a lower MCS.
An excellent illustrated coverage of electric and pneumatic MU systems and connections appeared in the Model Railroader Cyclopedia: Vol.2 Diesel Locomotives. Since this book is long out of print, maybe it is time for an update or, possibly run the section on MU in the magazine or as a special supplement. With a wide variety of model diesel locomotives on the market and modelers interested in properly employing them on their railroads, it is time for definitive guidance on this interesting subject. The latest locomotives covered by Vol. 2 are the EMD 645 powered Dash 2s and ALCo 251 powered C-628. Perhaps it is time for Vol 3 to bring us up to date on the wide nosed, flared radiator stuff that pulls trains today.
Baldwin ceased manufacturing diesel locomotives in 1956. While they did produce a small number of locomotives with electrical throttle, which could and did multiple with others, most Baldwin MU capable locomotives only MUed with other Baldwins.
Other observations, the PRR EMD power used 27 Point Jumpers, while ALCo RS3s used 21 point jumpers. Wilmington EH had several 27-21 adapter Jumpers available in case a EMD-RS3 MU was necessary. There was also a Jumper and Chart for Multipleing Electric E44 motors to Diesels equipped with 27 Point Jumpers.
Another factor determining whether or not a diesel would multiple was the air brake setup. Various railroads had different specifications. Most notable, again was the RS3, the NYC had a different MU Air set-up than the PRR. Made for some interesting situations.
Problem seemed to go away with second generation locomotives of all builders, having standardized the MU setup.
wojosa31 Another factor determining whether or not a diesel would multiple was the air brake setup. Various railroads had different specifications. Most notable, again was the RS3, the NYC had a different MU Air set-up than the PRR. Made for some interesting situations. Problem seemed to go away with second generation locomotives of all builders, having standardized the MU setup.
The problem with different locomotive air brake systems didn't go away with the second generation. Eventually standardization happened so today most every railroad's power capable of MUing will work with one another.
At one time, even within the same railroad, some equipment had to be MUed in a certain order.
http://www.rits.org/www/histories/Brakes74/PAGE1.HTM
http://www.rits.org/www/histories/Brakes74/PAGE21.HTM
Jeff
As you've read -- generally yes, except for the Baldwins. EMD, Alcos and GEs ran together all the time. There must have been modifications of non-compatible systems, as NYC ran older RSs, Fs and GPs together all the time. FMs were a bit tricky because of their high walkways... it was a long way down to that GP-9!
One possible exception is the Alco RS-1 -- I don't believe they all were equipped for MU operation. Look for the six hoses, three on either side of the coupler. If they're missing, I believe this means they do not have MU capability.
I'm not sure how much of an issue brake compatibility is. All of the first-gen locos I have climbed around had 24RL braking equipment, or had been rebuilt with newer 26L equipment, which are compatible with each other. I used to have a Chessie operating manual that mentioned 6BL equipment that might not have been fully compatible with the newer braking equipment -- I can't remember and the book is buried somewhere.
Generally a brake valve is a pretty simple piece of equipment, it's just a way of venting air from the brake pipe which makes the brake do its thing. However locomotive braking systems allow the loco brakes to be applied or released independently of the train brakes, hence the potential for compatibility issues.
If it's your own railroad, you can always say that your Baldwins were rebuilt with compatible MU systems. :)
HTH
Aaron
An excellent illustrated coverage of electric and pneumatic MU systems and connections appeared in the Model Railroader Cyclopedia: Vol.2 Diesel Locomotives.
The artwork and most of the illustrations in Volume 2 are reproduced from the December 1968 Trains article. Sadly the second colour (red) used to identify the throttle wires in the Trains article reproduced as grey or not at all. The text is less extensive and gives less historical detail.
Peter.