Question on multiple locomotives in a consist. Do they have to be the same make?

Amfleet25124 posted:

Pardon me is there is an obvious answer, but from what I can recall whenever I’ve seen freight trains in person (FEC and CSX here in South Florida), or online in photos and videos, the set of locomotives pulling the consist have always been of the same make.  What’s the reason for this? 

Generally just the luck of the draw, unless that railroad has a majority of that builder's units assigned to that service.

Because the locomotives have the same gearing? 

No.

Is there another reason?

See above answer.

I thought that all the locomotive were connected and running at the same notch. 

If they are all MU'ed AND "on the line", yes.

Has it always been this way or has it gone more in this direction in recent years? 

Yes, pretty much has always been that way, i.e. if they are MU'ed AND "on the line".

The only exception is that I’ve seen a couple times on Amtrak when a Dash 8 was operating with a P42 Genesis, where I’m guessing the Dash 8 was heading to/from the yard shops in Hialeah.

Kevin...the SIMPLE answer is,no they can be any make as long as they can MU with each other....Joe

With the MU configuration did all manufactures follow the same standard to make them universal? Could a GE mu with and Baldwin back in the day?

CSX FAN posted:

With the MU configuration did all manufactures follow the same standard to make them universal?

Yes, pretty much after the late 1950s or early 1960s. By the early 1970s, the AAR issued standards for each and every pin/wire within the 27 point MU jumpers, so manufacturers pretty much followed that standardization. 

Could a GE mu with and Baldwin back in the day?

Well, GE wasn't really making road diesels "back in the day", as the GE U25B road unit didn't come out until about 1961 or 1962. By then, Baldwin Locomotive works was pretty well gone.

Thanks for letting me know.  One learns something every day.  Needless to say, if and when I run a two locomotive consist, I'm going to make sure that the make/type of the second one purchased matches the first one in order to be 1:1 prototypical.

I recall reading somewhere that Baldwin wouldn't MU with other brands because it used pneumatic controls while other manufacturers (Alco & EMD) used electrical controls.

Amfleet25124 posted:

Thanks for letting me know.  One learns something every day.  Needless to say, if and when I run a two locomotive consist, I'm going to make sure that the make/type of the second one purchased matches the first one in order to be 1:1 prototypical.

What?  No, nobody indicated that the real railroads always MU the same manufacturers units together. How did you get such an idea?

RJR posted:

I recall reading somewhere that Baldwin wouldn't MU with other brands because it used pneumatic controls while other manufacturers (Alco & EMD) used electrical controls.

True.

Kevin:

I believe you misunderstood the responses.  Locomotives in a consist do not have to be the same make.

Curt

SD40-2's and GP9's playing together nicely in 1979:

GE U-25-B, F3B, SD9:

FM C-Liner and Alco PA1:

Krauss-Maffei and GP9:

Rusty

I read somewhere that in the early diesel years (‘50s) on the NYC they only MUed like manufacturers locomotives together. I am not saying they couldn’t have mixed different manufacturers together just that to my understanding this was their practice. And of course I can’t remember the reason as to why they did this or where I read it but this did stick in my head. Obviously, from this thread other railroads did things differently. 

I wonder how many guys will scour the Internet for a photo that proves me wrong? LOL

I recall in the 1960s that a couple of roads MU'd GE 44 and 70 ton locos for branch line or short line service.  The roads used Baldwins as well, but when the Baldwin and GE locos were operated together they needed separate crews.

Hudson J1e posted:

I read somewhere that in the early diesel years (‘50s) on the NYC they only MUed like manufacturers locomotives together. I am not saying they couldn’t have mixed different manufacturers together just that to my understanding this was their practice. And of course I can’t remember the reason as to why they did this or where I read it but this did stick in my head. Obviously, from this thread other railroads did things differently. 

I wonder how many guys will scour the Internet for a photo that proves me wrong? LOL

I think there's some truth in your post.

I started with CN in 1965   and good power was 3 or 4 GP9s  MU'ed     or       the same Alco versions   RS-11s. I'm sure there were exception but for the most part the GM and Alco were seldom MU'ed. Yes there were RS3s F units SWs but for the most part GPs and RS-11 handle the main traffic.  (at least in the Toronto area,)

 It was a fun time, experienced  4 & 5 man crews, small trains with caboose..Maybe 80 cars. single track CTC , Siding held about 90  cars with a power switch at one end and a Spring switch at the other.  No cameras ,  no black boxes .  Very seldom did we have a Trainmaster or company official riding along .

We were not long getting over the road,,,,

Clearly the diesel manufacturers were in a competitive race with one another. Unless one manufacturer had a locomotive that was so far superior to its competitors, that buyers would do a total motive power replacement, they needed to offer locomotives that were interchangeable with other diesel manufacturers.

I would feel certain that purchase specifications would contain requirements that the purchased locomotive would be interchangeable with the vast bulk of their motive power as far as MU capability is concerned. Those manufacturers who could not meet an interchangeability spec would soon find themselves out of business. (It may have taken a few years for buyers to start making that demand, but once they realized that option was technically economically accomplished, it would be a standard request) Disclaimer: This may not be factual, but if it isn’t, I’d question the business sharpness of the railroads.

TM Terry posted:

Clearly the diesel manufacturers were in a competitive race with one another. Unless one manufacturer had a locomotive that was so far superior to its competitors, that buyers would do a total motive power replacement, they needed to offer locomotives that were interchangeable with other diesel manufacturers.

The locomotives from EMD beginning in 1946, i.e. after WWII just that superior, that such MU ability was left to the desires of ALCO, Baldwin, Fairbanks Morris, etc.

I would feel certain that purchase specifications would contain requirements that the purchased locomotive would be interchangeable with the vast bulk of their motive power as far as MU capability is concerned.

You would think so, however such was NOT the case.

Those manufacturers who could not meet an interchangeability spec would soon find themselves out of business.

That is EXACTLY what happened to "all the others", especially when GE entered the road locomotive market in about 1961.

(It may have taken a few years for buyers to start making that demand, but once they realized that option was technically economically accomplished, it would be a standard request) Disclaimer: This may not be factual, but if it isn’t, I’d question the business sharpness of the railroads.

juniata guy posted:

Kevin:

I believe you misunderstood the responses.  Locomotives in a consist do not have to be the same make.

Curt

Been tied up since this afternoon and just getting around to checking on this thread

Yes I definitely misunderstood the responses.  Went through some of these posts when I got home and did some looking.  Believe it or not, I came across an old video on my own YouTube channel https://www.youtube.com/watch?...=19s  with an example of FEC lashup with two different locomotives LOL.  Usually when I come across a freight train at a railroad crossing the locomotives have passed by already. Other than that, as I mentioned above, everytime I see two or more units pulling a train, they are always the same make.

There were some serious incompatibility problems with first-generation diesel locomotive multiple-unit control systems, and they were not ironed out on some of the postwar locomotives until the 1960's, while other postwar diesels went to scrap having never successfully been made universal for m-u.

The biggest issue was the Wabco air throttle used by Baldwin, and by Fairbanks-Morse on a few early road switchers. Those engines were only able to m-u with other units with Wabco throttles, right to the end.

The second biggest issue was dynamic brake control.  EMD used a field loop, which required an additional 3-wire cable with rectangular connections, between every unit in the consist.  Alco used potential line control which used wiring in the main m-u jumper cable.  EMD did away with field loop control in the late 1950's, and could then m-u with Alco or GE units and the controlling unit could control dynamic braking throughout the consist.  On second-generation units, EMD offered optional field loop control with a selector switch to cut it in or out (used when a newer unit controlled older units with field loops).  SP had a number of EMD's built in the 1960's with this feature.  This was no handicap to roads such as the Rock Island, Missouri Pacific, Louisville & Nashville*, Canadian National, or Nickel Plate, which did not equip the majority (or, sometimes, any) their locomotives with dynamic braking.

Sanders were normally air controlled, but GE made an electrical sander control that was used on some Alco road engines and on F-M Erie-Builts.  Those units could not mu with EMD's because the controlling unit couldn't control sanding throughout the mixed consist.  Some railroads fixed this with shop modifications.  Later, in the second-generation units such as U25B's, Alco Century units, and EMD GP30's, the tide turned and electrically-controlled sanding became the desired method.  Many, many first generation units were then changed over to electrically-controlled sanding.

Union Pacific really marched to its own drum, requiring two (or three) jumper cables to operate its units.  Find a photo of a UP GP9 in the 1950's and look at the m-u receptacles on the end of the unit to see what this looked like.  Special jumper cables were required when Northern Pacific and Union Pacific GP9's were m-ued on the jointly-owned Camas Prairie Railroad in Idaho.  UP modified all of its engines -- except for its very few Baldwins, of course -- to single jumper cable m-u in the 1960's.

Railroad shops modified lots of first-generation diesels to eliminate m-u incompatibility when the lack of flexibility started to hurt, and to avail themselves of the cost savings of pooling locomotives to avoid engine changes on run-through trains.

And there were two kinds of jumper cables for EMD's: The 27-pin jumper which was universal (except for UPRR) beginning after World War II ended, and the 21-wire cable** used on FT's and, I believe E-units from EA through E6.  All railroads modified the small number of E-units, using special jumper cables in the interim, so they could m-u with postwar passenger diesels, but the FT's were a different situation.  Most roads did not mix their FT's with newer locomotives because FT's had manually-operated fans and radiator shutters, which kept the Fireman busy patrolling the engine rooms, reading the water temperature gauges, and operating the shutters and fans to maintain the desired temperature.  This worked best in solid FT consists.  Also, FT's were equipped with 8-EL air brake schedule, which worked fine with 24-RL but not with all 6-BL units (see next paragraph).

And there was some incompatibility between locomotives equipped with 24-RL air brake schedule (the postwar standard for freight and passenger locomotives) and certain units with 6-BL air brake schedule (Geeps on roads like Frisco, Burlington, and others that did not opt for 24-RL on road switchers.  This was cured by shop modifications when lack of flexibility dictated it on a given railroad.

So . . . you thought it was only air throttles?  

* The pre-merger  L&N, that is.  The NC&StL did have dynamic braking on its F3, F7 (and FP7?) units.  Never provoke the NC loyalists.  Just don't.  Trust me.

** I believe the number of wires was 21.  Hot Water may correct me if my memory has failed on this.

It is interesting to note that multiple units, today, can be controlled remotely, even when not  hard wire/cable connected. The new Marcellous Shale Gas collection site, Westland, Pa is serviced by  W&LE. (4 Units) used to move the tank cars up the grade out of Westland, Two (front), and Two (rear),  remote from each other, still controlled by one engineer.   Longer trains you may see helpers, mid-train, controlled remotely. 

Not and expert, only an observation, I'm sure, if wrong, I'll be corrected.

Mike CT posted:

Not and expert, only an observation, I'm sure, if wrong, I'll be corrected.

Safe!!!!

All correct.  

Now that is some solid info.  On my local CN line that runs through town I see all types of different units MUed together.  Sometimes different paint on them as well.  It does seem on the unit trains, like all containers, they will put like engines in the train, sometimes with one in the middle, and sometimes with one at the end.  On the mixed freight trains I see more of an assortment.  And every once in a while a BC Rail guy, my favorite.  These are all MUed at the front end.  I'm sure they've got it down to a science, so to speak.  It would make sense that putting the same type of engine in the unit trains would be beneficial, in that their performance matches, making for a smoother ride overall, especially when they are mid train or at the rear.  For the mixed freights it can be a hodge podge of the necessary horsepower to pull the train at the front end.  Just an observation.  I'm no expert.

Some good, solid and CORRECT information from Tom, as usual. Thanks!

Good to know all these details about locomotive lashups...er...I mean locomotive consists. 

William 1 posted:

Now that is some solid info.  On my local CN line that runs through town I see all types of different units MUed together.  Sometimes different paint on them as well.  It does seem on the unit trains, like all containers, they will put like engines in the train, sometimes with one in the middle, and sometimes with one at the end.  On the mixed freight trains I see more of an assortment.  And every once in a while a BC Rail guy, my favorite.  These are all MUed at the front end.  I'm sure they've got it down to a science, so to speak.  It would make sense that putting the same type of engine in the unit trains would be beneficial, in that their performance matches, making for a smoother ride overall, especially when they are mid train or at the rear.  For the mixed freights it can be a hodge podge of the necessary horsepower to pull the train at the front end.  Just an observation.  I'm no expert.

Yep.... The railways are going to use their best power on high revenue  trains,  Intermodal.  Unit coal/ ore trains even rough freight  Lumber, paper etc.

However. .You're probably going to find an assortment of power  on trains  that run locally , perhaps a stone train/  ballast train....pickups from different yards  Etc...

The ore train I worked usually had 4 SD-40s... 24 motorized axles .  4 Alco equivalent (2300s) 24 motorized axles  or 5 GP40s (20 motorized axles  ( all engines were 3000 HP)

 All would handle the train but which do you think was the favourite  with crews.

Gregg posted:

William 1 posted:

Now that is some solid info.  On my local CN line that runs through town I see all types of different units MUed together.  Sometimes different paint on them as well.  It does seem on the unit trains, like all containers, they will put like engines in the train, sometimes with one in the middle, and sometimes with one at the end.  On the mixed freight trains I see more of an assortment.  And every once in a while a BC Rail guy, my favorite.  These are all MUed at the front end.  I'm sure they've got it down to a science, so to speak.  It would make sense that putting the same type of engine in the unit trains would be beneficial, in that their performance matches, making for a smoother ride overall, especially when they are mid train or at the rear.  For the mixed freights it can be a hodge podge of the necessary horsepower to pull the train at the front end.  Just an observation.  I'm no expert.

Yep.... The railways are going to use their best power on high revenue  trains,  Intermodal.  Unit coal/ ore trains even rough freight  Lumber, paper etc.

However. .You're probably going to find an assortment of power  on trains  that run locally , perhaps a stone train/  ballast train....pickups from different yards  Etc...

The ore train I worked usually had 4 SD-40s... 24 motorized axles .  4 Alco equivalent (2300s) 24 motorized axles  or 5 GP40s (20 motorized axles  ( all engines were 3000 HP)

 All would handle the train but which do you think was the favourite  with crews.

 

 

The SD40's of course

In all my railfanning in "modern" I have seen lots and lots of mixed consists of GE and EMD locos.    I was too late to see Alcos in mainline service.    I still see mixed consists as near as I can tell.

I think keeping the same mfg was more common early on.    As an example, a friend of mine was entertaining the NYC historical society at layout open house.     He was running some trains that had Alco and EMD mixed consists.    One of the attendees, a retired NYC employee, told him that during his era of the mid 50s, that did not happen on NYC.    He said the reason was that the MU connections were incompatible.    We have all heard this about Baldwin.    But he said even though technically the Alco and EMD connections were the same or similar, the cabling and connectors were not.   He said this went on until the units were about 15 years old, and went through their first major overhaul and rebuild.    During that they were all rebuilt (possibly no baldwin) to be compatible in their MU connections.    And then NYC did a lot of mix and match.   He implied this happened in the early 60s.    

Baldwin on most units used some sort of air operated MU system that was totally incompatible with the electric ones used by EMD and Alco.  

I have that RRs did not like to mix locos with widely different gearing too.    This tended to cause the traction motors in one or the other  unit to overheat.    This referred to running passenger locos mixed with freight, EMD Fs and Es together for example, without regearing the passenger units. 

Hot Water posted:

RJR posted:

I recall reading somewhere that Baldwin wouldn't MU with other brands because it used pneumatic controls while other manufacturers (Alco & EMD) used electrical controls.

True.

Apparently some were converted.  I saw a video of a Baldwin roadswitcher MU'd with a Geep on the Escanaba & Lake Superior, taken in the 1990's.  The very different exhaust notes mixing together was interesting.

Lehigh Valley Railroad posted:

Gregg posted:

William 1 posted:

Now that is some solid info.  On my local CN line that runs through town I see all types of different units MUed together.  Sometimes different paint on them as well.  It does seem on the unit trains, like all containers, they will put like engines in the train, sometimes with one in the middle, and sometimes with one at the end.  On the mixed freight trains I see more of an assortment.  And every once in a while a BC Rail guy, my favorite.  These are all MUed at the front end.  I'm sure they've got it down to a science, so to speak.  It would make sense that putting the same type of engine in the unit trains would be beneficial, in that their performance matches, making for a smoother ride overall, especially when they are mid train or at the rear.  For the mixed freights it can be a hodge podge of the necessary horsepower to pull the train at the front end.  Just an observation.  I'm no expert.

Yep.... The railways are going to use their best power on high revenue  trains,  Intermodal.  Unit coal/ ore trains even rough freight  Lumber, paper etc.

However. .You're probably going to find an assortment of power  on trains  that run locally , perhaps a stone train/  ballast train....pickups from different yards  Etc...

The ore train I worked usually had 4 SD-40s... 24 motorized axles .  4 Alco equivalent (2300s) 24 motorized axles  or 5 GP40s (20 motorized axles  ( all engines were 3000 HP)

 All would handle the train but which do you think was the favourite  with crews.

 

 

The SD40's of course

Hee Hee  I can understand your answer after looking at your profile... Cadillac Service manager.. and yes the SD-40 were very comfortable riders just like  a Cadillac.

However our crews like the 5 GP40s with  Canadian Comfort Cabs.... Very reliable .    

As for the Alcos ....  Well    I was always happy  to get off the thing when the trip was over,,, Rough riders..They did handle the train though.

Thanks for taking part.

prrjim posted:

In all my railfanning in "modern" I have seen lots and lots of mixed consists of GE and EMD locos.    

 

This is an everyday occurrence in modern railroading.....

I believe I was thinking about the same question RJR posted about MU between Alco and EMD that there was a problem. I remember something about that case. 

different question what about the power mismatch between MU'd Locomotives. Would there be a large issue between say the example above where you have a 44 tonner with a 70 tonner.  wouldn't the 44 get worked to death? 

CSX FAN posted:

I believe I was thinking about the same question RJR posted about MU between Alco and EMD that there was a problem. I remember something about that case. 

As a general statement, MU'ing EMD and Alco units, back in the early days had only one "issue", which was "open series contactors", which Alco  had. In other words, whenever an Alco unit was leading an EMD MU consist, every time the Engineer reduced the throttle to "idle", all the power contactors in the whole consist would open. The EMD units didn't like THAT at all, as EMD units had "closed series contactors", which means that the power contactors pick-up (close) when the reverser is thrown, and thus reducing the throttle to idle does NOT affect the switch gear.  

 

different question what about the power mismatch between MU'd Locomotives. Would there be a large issue between say the example above where you have a 44 tonner with a 70 tonner.  wouldn't the 44 get worked to death? 

Not really, as each unit in the MU'ed consist only does whatever it can do.

CSX Fan, are you in the process of acquiring a 70-tonner?

In a past OGR Rich Melvin wrote that he was controlling a diesel-electric from the cab of the NKP 765 - it was "MU'ed" - and he could dial up the notches when he needed extra power.