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Questions About Locomotive Lashups

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Posted by Deggesty on Sunday, February 15, 2015 8:43 PM

Looking back over a trifle more than sixty years of interest in railroad operation, I recall that David P. Morgan used the term "lashup" to describe the coupling of two or more locomotives (and, back then, unless an engine was a helper with its own crew all of the engines were coupled together). It is possible that the term is now used in the industry to describe a mixture that is not the best.

Johnny

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Posted by beaulieu on Sunday, February 15, 2015 7:23 PM

Diesel Locomotives can produce their maximum horsepower and pulling power going forward or backwards. It is because they have an electrical transmission rather than a mechanical transmission like a truck. An electrical motor can produce the same amount of power no matter which way its shaft rotates. Interchange two wires that are feeding power to the motor and you change the rotation. As to the seemingly random way that the locomotives are facing, the crews want the lead locomotive facing forward if at all possible, other than that, they tend to be left the way they were facing at the time they were put together. With repect to whether all the power is on the head-end or split with one or more in the middle or on the rear, that depends on the amount of power allocated and the weight of the train. Too much power on the Head-end can break couplers. Putting locomotives in the middle of the train requires additional time to arrange the cars and the locomotives. Now it seems the first choice is to put the single locomotive on the rear as it is easier than splicing it into the middle. Manned pusher or helper locomotives are no used only in those situations where the additional power is only needed for a few miles, with remote controlled locomotives (DPU) used where there are multiple locations where the extra power is needed and where the extra power would be too much if it was all on the Head-end. As surprising as it may seem, two locomotives split one on the Head-end and one pushing on the rear can move more tonnage than the same two locomotives both pulling from the front. 

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Posted by PNWRMNM on Sunday, February 15, 2015 2:43 PM

Paul,

That unit on the rear end was 99.99% likely to have been a DPU.

Mac

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Posted by samfp1943 on Sunday, February 15, 2015 2:18 PM

Paul Milenkovic wrote the following(in part):

[snipped]:"...I have one question for our panel of experts.  My wife and I were watching a long train of tank cars pass the Water Plank Road crossing of the CP in Elm Grove, Wisconsin near Milwaukee.  I took some pictures, and my wife said, "I know you like to watch trains, let's wait for the caboose to go by."

I was going to say, "Honey, modern trains no longer have a caboose" but for you guys who have been married a long time, I kept that thought private.  Sure enough, this train had a "caboose" in the form of a trailing locomotive, facing to lead the train were the train to change directions..."

Just a note Paul:  Sometimes, Prudence is the better part of valor.  A spoken response/retott? to that kind of remark can land a husband on that 'mystical scale of wifely responses' Hmm  : somewhere between THAT LOOK, and Homicide.Sigh 

The important factor to remember is that wives like Elephants...NEVER, EVER FORGET.  Whistling

 

 


 

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Posted by Paul Milenkovic on Sunday, February 15, 2015 9:25 AM

In an episode of Buck Henry and Mel Brooks' "James Bond" spoof "Get Smart", Maxwell Smart is guarding the young and beautiful but naive Contessa.  A KAOS agent (it took me years to realize that the word for disorganization is "chaos") enters the room and holds them at gunpoint.  A CONTROL agent steps out from behind the curtains and pulls a gun on the KAOS man.  This continues as KAOS and CONTROL agents appear out of nowhere and each points a gun on the next guy.

This forms a Conga line of spies, one pointing a gun at the next.  The Contessa asks Max, "What happens now?"  Max replies with his expertise on spy "tradecraft", "Nothing happens.  This is what 'we in the business' call a stand-off.  We just walk out of here . . ." after which we hear "blam-blam-blam" of gunfire and see the line of spies down on the ground.  "Of course, it takes just ONE idiot!"

It is great that we have people with expert knowledge to respond to a new person's question, but it might take just one harsh response to discourage a newcomer.

Both the words "lashup" and "consist" are used to describe the coupling of multiple locomotive units using the multiple-unit (MU) connections and controls to effect a single locomotive operated by a single set of controls.  Yes, lashup is more of a railfan term whereas consist is more official railroad nomenclature, but there must have been a railroad employee calling it a "lashup" before being slapped with a hat on the side of his head as the Skipper did to Gilligan. 

Yes, lashup is probably more descriptive of the older practice of mix-and-match of different models or unit or even units of different manufacturers; these mongrel sled teams are more rare today with the increased sameness of Class 1 motive-power pools and locomotive assignments.  Also, even though the word "lashup" got used, even on the print page of Trains Magazine, railfans in-the-know are more inclined to use the word "consist."

There is one aspect to distributed power not brought up.  Yes, distributed power is easier on the couplers and favored if you have a long train on a steep grade requiring many locomotive units.  But distributed power either requires specialized equipment for the remote control of trailing units by radio link.  That radio link can also cut out if the train enters a tunnel, so the engine driver needs to anticipate this.  Or, extra crews are needed to operate the locomotives, as with a "helper district" where another consist pushes on the rear of the train.

Furthermore, distributed power may require more switching in making up a train to locate the locomotive units that way.  On the flat land and with shorter trains, it is simpler to lash up, er I mean, form a consist of locomotive units at the head end.

I have one question for our panel of experts.  My wife and I were watching a long train of tank cars pass the Water Plank Road crossing of the CP in Elm Grove, Wisconsin near Milwaukee.  I took some pictures, and my wife said, "I know you like to watch trains, let's wait for the caboose to go by."

I was going to say, "Honey, modern trains no longer have a caboose" but for you guys who have been married a long time, I kept that thought private.  Sure enough, this train had a "caboose" in the form of a trailing locomotive, facing to lead the train were the train to change directions.

Is this a common practice to allow a reverse move of this long unit train?  Or maybe that locomotive was just added to the train for "deadheading"?

If GM "killed the electric car", what am I doing standing next to an EV-1, a half a block from the WSOR tracks?

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Posted by Diesel Power on Saturday, February 14, 2015 3:01 PM

GDRMCo
"Again I'm assuming it has to do with horse power." Curious to know why you think this....(in regards to direction locomotive is facing)

 
Well, again coming from a complete train newb and not knowning the full functions of a locomotive; my guess is that depending on how the locomotive was designed, some locomotives will provide more horse power running forward as compared to backward. Then again they could run the same horse power in either direction. Again I don't know (hence the question) but my initial thought tells me that a locomotive would provide more horse power going in a forward direction. Of course we all know what happens when one assumes. LOL

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Posted by Wizlish on Saturday, February 14, 2015 10:02 AM

Diesel Power
Newbie here with a dumb question about locomotive lashups.

Bear in mind that what you're discussing is better called a "consist", not "lashup" (which refers to mismatched units or 'kludged' arrangements; see the historical meaning of the word).  I think there's an implicit semantic analogy between the horses' reins and the MU cabling (or control air on Baldwins) ... but I think your request will be taken more seriously if you do not use the railfan term.

There have been several discussions on this subject, but without a functional forum-search you're unlikely to find them easily.  Yet another good reason to avoid thread drift is that some of the discussion may be in posts with a completely different title in the thread list, making it essentially on the moon to newbies looking for information in the great mass of older postings.

1. Why are some locomotives front facing and others rear facing in the lashup. I'm assuming it has to do with horse power needed for the consists but not sure what benefit a front facing or rear facing locomotive has over the other.

Usually you'd want the cab leading in front (easier to use the controls; the diesel engine exhaust is behind you in confined spaces and tunnels), although the locomotive generally pulls equally well in either direction.  When using two units in general freight work it's common to see them coupled 'cabs-out' as this produces the effect of a larger double-cab locomotive.  On the other hand, on unit coal trains you often see 'elephant style' (more than one cab facing forward) so that if the lead engine develops a problem the one behind it can be used to run the train normally. 

I have seen trailing power with cabs facing either in the direction of movement (easy to move to the 'point' if there is a road failure there, or have all the power facing the same way if pooled) or toward the rear (perhaps to simplify bidirectional movement).  I saw a coal train yesterday (BNSF power) that had cabs in on the trailing power (!) - bet other railfans have pictures of this already

2. With consists that have a locomotive attached to the rear, why do they sometimes have them front facing and at times rear facing? Again I'm assuming it has to do with horse power.

See above.  Others more knowledgeable about specific operations will say why they prefer one to the other ... or what factors make it a choice vs. an accident.  To my knowledge DP power runs equally well in either direction, provided the equipment has been configured to run in forward/reverse appropriately at 'run time'.  In tunnels there might be an advantage in keeping the radiators ahead of the engine exhaust.

3. What is the benefit if the additional power is added to the front of the train (ie 3 locomotives at the front, 1 locomotive in the rear) compared to more spread out power (ie 2 locomotives in the front, 2 locomotives in the rear), compared to all the locomotives at the front (ie 4 locomotives in front and none in the rear)? I'm assuming it has to do with the consists that's being hauled and the horse power needed to move it.

Less to do with the 'horsepower needed to move it' than with how that horsepower is communicated to the train through the couplers and draft gear.  (There are good discussions on this subject in past threads, too.)  When the power is divided (either with midtrain or EOT DPU) there is less drawbar stress in the cars ... in fact, at some point in the train (known as a 'node') there will be no drawbar stress at all.  Since both couplers and drawgear have a limited (though high) breaking strain, and the likelihood of a break is much greater if shock or slack action is involved, minimizing the peak draft force on any car in a long and heavy train is important.

Since some slack is desirable in starting a long train, it used to be common to find more power on the point than as trailing power, which allows the front part of the train to be started conventionally ('car-by-car') before the trailing power has to start shoving hard.  There are good reasons why there will be more power on the 'point' than either midtrain or trailing.

4. I live in the Pacific Northwest and the bulk of trains that we see are BNSF as that's who owns the track in my area. I was curious to know why sometimes you'll see a BNSF train with additional power from CP, CN, CSX and/or NS?  I find it weird that a BNSF train would have another train line's locomotive attached to the consists.

See previous posts on pooled equipment, leased equipment, etc., as well as 'run-through arrangements'.  We had a good one recently, regarding how this power is paid for (the assumption being that a unit is billed as producing its peak horsepower continually during the "offroad" time, with no discount for lower levels of usage or when parked).  If you can get to the Forum search engine, there was a good discussion of pure leased power if you search on "Citirail".

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Posted by GDRMCo on Saturday, February 14, 2015 9:15 AM
"Again I'm assuming it has to do with horse power." Curious to know why you think this....(in regards to direction locomotive is facing)

ML

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Questions About Locomotive Lashups
Posted by Diesel Power on Friday, February 13, 2015 4:04 PM

Newbie here with a dumb question about locomotive lashups.  Sorry if this has been posted before, but I searched several pages and didnt see anything listed. So my son had a few questions, and me too for that matter regarding how locomotives were connected together.

1. Why are some locomotives front facing and others rear facing in the lashup. I'm assuming it has to do with horse power needed for the consists but not sure what benefit a front facing or rear facing locomotive has over the other. 

2. With consists that have a locomotive attached to the rear, why do they sometimes have them front facing and at times rear facing? Again I'm assuming it has to do with horse power.

3. What is the benefit if the additional power is added to the front of the train (ie 3 locomotives at the front, 1 locomotive in the rear) compared to more spread out power (ie 2 locomotives in the front, 2 locomotives in the rear), compared to all the locomotives at the front (ie 4 locomotives in front and none in the rear)? I'm assuming it has to do with the consists that's being hauled and the horse power needed to move it.

4. I live in the Pacific Northwest and the bulk of trains that we see are BNSF as that's who owns the track in my area. I was curious to know why sometimes you'll see a BNSF train with additional power from CP, CN, CSX and/or NS?  I find it weird that a BNSF train would have another train line's locomotive attached to the consists. The other day I caught 3 NS locomotives hauling a freight consists with no BNSF trains attached at all. I've never seen that before and was curious why the NS was way out of its territory. I thought the NS locomotives would have hauled the consists to another yard where the consists would then be picked up by another line, in this case BNSF as that's the territory it was going to. Any thoughts on this?

Thanks to any information and and answers you can provide.

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