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Locomotive placement

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Locomotive placement
Posted by NKP guy on Wednesday, April 1, 2020 2:06 PM

   Lately as I observe CSX trains on the old B&O near Akron I have seen trains with one locomotive on the head end and then another mid-train.  Other trains have one locomotive at each end of the train.

   Why?  Is there an advantage to doing it one way or the other?  And why is simply putting all the power on the head end not done?

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Posted by BaltACD on Wednesday, April 1, 2020 4:42 PM

NKP guy
   Lately as I observe CSX trains on the old B&O near Akron I have seen trains with one locomotive on the head end and then another mid-train.  Other trains have one locomotive at each end of the train.

   Why?  Is there an advantage to doing it one way or the other?  And why is simply putting all the power on the head end not done?

One of the theories being applied with distributed power is that it reduces the in train buff and draft forces as well as giving the engineer a greater ability to to control the slack adjustment that happens within the train.

Akron is the ruling grade between New Castle and Willard - a little over 1% in each direction from Akron Jct which is the bottom of the grade.  At one time there was a permanent 10 MPH speed restriction at Akron Jct, thus trains could not 'make a run' for the grade.

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Posted by timz on Thursday, April 2, 2020 5:16 PM

UP used to have a rule that the DPU couldn't be more than 8500 ft from the head end. Maybe still does?

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Posted by jeffhergert on Thursday, April 2, 2020 10:13 PM

timz

UP used to have a rule that the DPU couldn't be more than 8500 ft from the head end. Maybe still does?

 

Yes.  And No.  Depends on the type of train.  Some are allowed 10,000 ft.

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Posted by pennaneal on Tuesday, April 21, 2020 7:45 AM

wonder if you could expand your answer. I've also been wondering about engine placements being so varied. I don't get to see a lot of long trains but all videos including more recent with more powerful engines still use multiple engines in all configurations. is it all weight distribution? How much less horsepower to pull passenger trains? Thanks still learning.

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Posted by 1019x on Tuesday, April 21, 2020 9:28 PM

A passenger train might weigh 800 to 1,500 tons. A heavy freight train could weigh as much as 16,000 tons or more.

 

pennaneal

wonder if you could expand your answer. I've also been wondering about engine placements being so varied. I don't get to see a lot of long trains but all videos including more recent with more powerful engines still use multiple engines in all configurations. is it all weight distribution? How much less horsepower to pull passenger trains? Thanks still learning.

 

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Posted by soo_gp9 on Tuesday, May 5, 2020 9:50 AM
Per reply above, draft gear forces are an important consideration but another consideration are forces on the rails. This is demonstrated by place a string in a half circle. Pull one end, what happens? Push one end, what happens? Strategic placement of engines, as shown in string example, also reduce the amount of rail friction the engines need to overcome. Curves, like grades, require more power.
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Posted by blue streak 1 on Wednesday, May 6, 2020 3:57 AM

What is interesting around here is CSX operating practices.  Most DPU trains here are operated with a 1x1x0 operation with a few a 1x1 operation.  At my location is a sag with northbound being the ruling grade.  The middle or rear DPU is almost always in run 8 and the lead loco at whatever the train tonage requires for MAS.  If train apparently very light front at idle and back whatever needed. 

If train slowing for stop mid train DPU full dynamic braking and slow application of brakes for final stopping.

Notice a lot less rail squeel

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Posted by MMLDelete on Wednesday, May 6, 2020 11:02 PM

blue streak 1

What is interesting around here is CSX operating practices.  Most DPU trains here are operated with a 1x1x0 operation with a few a 1x1 operation.  At my location is a sag with northbound being the ruling grade.  The middle or rear DPU is almost always in run 8 and the lead loco at whatever the train tonage requires for MAS.  If train apparently very light front at idle and back whatever needed. 

If train slowing for stop mid train DPU full dynamic braking and slow application of brakes for final stopping.

Notice a lot less rail squeel

 

Could you please explain 1x1 vs. 1x1x0. Thanks.

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Posted by jeffhergert on Wednesday, May 6, 2020 11:48 PM

1x1 = one engine in the lead, one engine at the very rear.

1x1x0 = one engine in the lead, one engine mid-train and no engine at the very rear.

That's the common understanding.  Someone may also mean one engine consist instead of a single engine.  When we have doubled up coal trains, some end up being a 2x3x1 configuration.  Two engines in front, three engines mid-train and one engine at the very rear.

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Posted by MMLDelete on Thursday, May 7, 2020 12:52 PM

Thanks, Jeff.

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Posted by pennaneal on Tuesday, May 12, 2020 7:28 AM

Thanks, one more question. How much does this have to do with the age and performance levels of these engines in use today?

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Posted by Overmod on Tuesday, May 12, 2020 7:56 AM

pennaneal
How much does this have to do with the age and performance levels of these engines in use today?

Of course it presupposes that all the engines that need to control 'power blocks' in a train are physically equipped with DPU equipment.

Ideally you'd want AC rather than DC equipment in the distributed consists, as it simplifies some of the potential undetected-slip events that could happen with remote locomotives.  Likewise, within a particular MUed distributed installation you might want to spec locomotives with similar loading characteristics so the application of power is a bit more predictable for train handling.

In theory you could install Locotrol III in much older locomotives, or MU antiques that use the same MU cable conventions into DPU consists.  What is happening recently is that a number of Class Is are consolidating operating power into just a few classes of the most reliable (or fuel-efficient, or whatever floats their perceived PSR/shareholder boat) locomotives, presumably most or all of which will be set up with the DPU radio system if they are expected to lead.

The assumption I have always had is that whoever makes up the power for a given train carefully assesses what power to use, and where in the train or consist block it should go, and makes any more specific locomotive-type allocation as part of that (this includes which way some or all the cabs would be pointing, a more interesting issue than you might think).  This would include "performance level" both as built and as perhaps degraded due to 'known but not yet critical' maintenance or repair issues.

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Posted by BaltACD on Tuesday, May 12, 2020 11:39 AM

Overmod
The assumption I have always had is that whoever makes up the power for a given train carefully assesses what power to use, and where in the train or consist block it should go, and makes any more specific locomotive-type allocation as part of that (this includes which way some or all the cabs would be pointing, a more interesting issue than you might think).  This would include "performance level" both as built and as perhaps degraded due to 'known but not yet critical' maintenance or repair issues.

False assumption - what power is currently available that can move the tonnage to be moved in a On Time timeframe is the only consideration that is applied.

Can't speak to other carriers.  Since about 2010 all the power CSX was buying was being equipped to operate in DPU service - both as leaders and as mid or rear of train operators.

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Posted by Overmod on Tuesday, May 12, 2020 3:57 PM

BaltACD
False assumption - what power is currently available that can move the tonnage to be moved in a On Time timeframe is the only consideration that is applied.

I presupposed in saying 'assesses what power to use' that whoever was making up the consist would do so from the power available to him.

I'm a bit surprised that CSX wouldn't be at least cognizant of keeping cabs available in case of road failure -- whether that's having the engine behind the point 'elephant-style' or arranging DPU to run around the train to lead 'cab-first'.

We have an amusing number of intermodal trains leaving Memphis on the ex-Southern NS that are long-hood-forward on the point to well east of Collierville.  On the other hand there was evidence of careful 'handing' of units (first in cabs-out pairs and later elephant-style) on UP run-through power, and BNSF has gone through a couple of paradigm changes but maintained consistency between.  

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Posted by zugmann on Tuesday, May 12, 2020 3:59 PM

Overmod
We have an amusing number of intermodal trains leaving Memphis on the ex-Southern NS that are long-hood-forward on the point to well east of Collierville.  On the other hand there was evidence of careful 'handing' of units (first in cabs-out pairs and later elephant-style) on UP run-through power, and BNSF has gone through a couple of paradigm changes but maintained consistency between.  

I don't think UP or BNSF puts ditch lights on the long hood end of road power. NS does.  Allows them to run track speed long hood first. 

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Posted by jeffhergert on Tuesday, May 12, 2020 9:05 PM

No ditch lights on the long hood end of modern six axle road power.  Only engines used mainly for yard and locals might have ditch lights, including the rebuilt SD40-2 engines for yard/local service.

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Posted by SD70Dude on Tuesday, May 12, 2020 9:46 PM

Pretty much all of CN's road units built or rebuilt since the mid-1990s have rear ditchlights.  Some of them even work properly when MU'd with other units.  

For some reason ($$$?) they recently stopped ordering rear pilots on new units, which limits them to 25 mph when that end is leading a movement.

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Posted by BaltACD on Tuesday, May 12, 2020 10:51 PM

Overmod
 
BaltACD
False assumption - what power is currently available that can move the tonnage to be moved in a On Time timeframe is the only consideration that is applied. 

I presupposed in saying 'assesses what power to use' that whoever was making up the consist would do so from the power available to him.

I'm a bit surprised that CSX wouldn't be at least cognizant of keeping cabs available in case of road failure -- whether that's having the engine behind the point 'elephant-style' or arranging DPU to run around the train to lead 'cab-first'.

Remember - CSX loads trains to MAXIMUM TONNAGE - failure of one engine brings the train to a halt - hopefully not in the middle of a single track segment.  If the failure is in a single track segment - another train will use its power, in addition to the failed train's power to move it to a siding to await a 'final solution' to its power issues.  The 'go to' solution is to steal an engine from a empty traing (coal, ethanol, oil or any other empty unit train that is running with more than a single unit).

The standard power, when I was working, was a pair of AC's back to back.  DPU was not being used when I was working.

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Posted by traisessive1 on Thursday, May 14, 2020 12:53 PM

SD70Dude

Pretty much all of CN's road units built or rebuilt since the mid-1990s have rear ditchlights.  Some of them even work properly when MU'd with other units.  

For some reason ($$$?) they recently stopped ordering rear pilots on new units, which limits them to 25 mph when that end is leading a movement.

 

 
I have never understood this. Why 25mph? I have watched numerous videos from US Class Ones runing LHF going much faster than 25 and they have no rear pilot. It seems like a stupid rule in my opinion. 
 
One thing not mentioned here about the use of DP is the ability to put more tonnage on the same train without adding more power. Sure the advantages to air and equipment/rail stress are good, but the big thing is moving more tonnage without more power. 

10000 feet and no dynamics? Today is going to be a good day ... 

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Posted by BaltACD on Thursday, May 14, 2020 4:11 PM

traisessive1
 
SD70Dude

Pretty much all of CN's road units built or rebuilt since the mid-1990s have rear ditchlights.  Some of them even work properly when MU'd with other units.  

For some reason ($$$?) they recently stopped ordering rear pilots on new units, which limits them to 25 mph when that end is leading a movement. 

I have never understood this. Why 25mph? I have watched numerous videos from US Class Ones runing LHF going much faster than 25 and they have no rear pilot. It seems like a stupid rule in my opinion. 
 
One thing not mentioned here about the use of DP is the ability to put more tonnage on the same train without adding more power. Sure the advantages to air and equipment/rail stress are good, but the big thing is moving more tonnage without more power. 

Personally, I find the whole ditch light thing as being stupid.  I am speaking from a US viewpoint - not the Canadians which originated the devices.

That being said - Rules are Rules.  FRA rules in the US limit engines with only the head light showing its direction of movement to 20 MPH over road crossings.  While two ditch lights are required, trains can operate at normal speeds if one becomes defective inroute, the defective light must be repaired at the next 'repair facility!.  Crew change locations, by themselves, are not a repair facility.

For a period of time CSX was pushing the operation of single unit trains - trains that in many cases were terminating at locations without turning facilities for engines.  None of the AC power or EVO power that CSX has bought over the last quarter century has been equipped with ditch lights on the long hood end.  

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Posted by MMLDelete on Thursday, May 14, 2020 11:23 PM

What is the reason to limit the speed of an engine without a pilot on the leading end?

is it that pilot-less engines make for messier grade crossing accidents?

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Posted by BaltACD on Friday, May 15, 2020 6:44 AM

Lithonia Operator
What is the reason to limit the speed of an engine without a pilot on the leading end?

is it that pilot-less engines make for messier grade crossing accidents?

There is a theory that people don't perceive motion from a single point of light in the same way they perceive motion from multiple points of light and are therefore 'fooled' into thinking the single point of light is traveling slower than the multiple points of light and thus misjudge the distance from the road crossing and the time they have to cross over said crossing.  The FRA ascribes to that theory and has ruled that there must be ditch lights in addition to the headlight to warrant track speed operation.

My theory is the some people are just bad judges of moving objects at road crossings or highway intersections in the non-railroad world.  Needless to say there are many more collisions at highway intersections than there are at rail-roadway road crossings.

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Posted by CSSHEGEWISCH on Friday, May 15, 2020 10:07 AM

With all due respects, it is difficult to determine the speed of something directly approaching you with only one point of reference.

The daily commute is part of everyday life but I get two rides a day out of it. Paul
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Posted by zugmann on Friday, May 15, 2020 10:18 AM

What do we mean by "no pilot"?  As in no anti-climber? 

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Posted by zugmann on Friday, May 15, 2020 10:23 AM

BaltACD
he defective light must be repaired at the next 'repair facility!.  Crew change locations, by themselves, are not a repair facility.

CFR says it's before the next calendar day inspection. But a RR can further restrict. 

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Posted by Overmod on Friday, May 15, 2020 10:24 AM

zugmann
What do we mean by "no pilot"?  As in no anti-climber? 

I'm pretty sure that (in this context) it would refer to the structure called for in the relevant section here:

https://www.railcan.ca/wp-content/uploads/2017/05/Railway-Locomotive-Inspection-and-Safety-Rules_EN.pdf

When I try to open this, my computer actually starts rendering other PDF documents upside-down, which I didn't think was intellectually, let alone technically possible, so you are going to have to do the checking for a while while I find some screwdrivers and heat-sink paste...

 

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Posted by Paul of Covington on Friday, May 15, 2020 2:31 PM

zugmann

What do we mean by "no pilot"?  As in no anti-climber? 

 

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Posted by kgbw49 on Friday, May 15, 2020 5:20 PM

I am guessing they mean the snowplow blade.

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Posted by SD70Dude on Friday, May 15, 2020 10:31 PM

It turns out that CN believes a "pilot" is a plow/wedge shaped thingy (not nearly as catchy as "yellow thingy" eh?).  Until a recent bulletin came out listing which locomotives have pilots came out, I and many others had believed that the flat, thick steel sheet met the definition. 

2599 has a rear pilot:

http://www.railpictures.ca/?attachment_id=18133

2528 does not:

http://www.railpictures.ca/?attachment_id=37831

Here is the worst type of locomotive to run backward, doing exactly that.  Note the lack of ditchlights, to go along with no pilot and half a headlight.

https://www.youtube.com/watch?v=GmSl1d3VLLk

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