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Locomotive Idle

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Locomotive Idle
Posted by PJS1 on Saturday, April 22, 2023 10:35 PM

Today, while visiting Temple, TX, where BNSF has a locomotive service facility, I saw and heard an SD60 idling.  No one was in the cab.  Periodically, the ide speed would increase noticeably for five minutes or so and then fall back to the lower speed.  Since no one was in the cab, what caused the idle speed to change. 

I have counted as many as 24 locomotives being serviced at the facility.  I am not sure I can see all of them from my perch across the tracks.  Many of them idle for hours.  Would the fuel consumed and the pollutants generated while the locomotives are idling be counted in the railroad's total fuel and air pollution statistics when compared to truck, air, water, etc.?  

Rio Grande Valley, CFI,CFII

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Posted by Overmod on Sunday, April 23, 2023 5:30 AM

Among other things, the idle might adjust to raise coolant or oil temperature, or preclude exhaust deposits in the manifold, or when air compressors cut in.  I surmise this is not loadboxing or other engine testing, just standby of idle locomotives.

I suspect that bogie engineer can give you very good technical information for EMD engine control, and there are others (including Preston Cook) on RyPN who know how to find anything they don't already know.

A great deal of time and effort is involved in starting a shut-down prime mover, and arrangements might have to be made to fire up a Hotstart or other protection.  Not all these engines have proper prelubers, either.  It could be facile for a government or agency to think that extending a truck idling mandate to railroads would enhance pollution abatement -- a certain set of comments about smoke drifting across the road in Roseville comes to mind -- but they may not have watched enough cold engine starts...

I fall back on the tired old line 'railroads are concerned with the OR and idling cuts into that if properly considered... so there have to be reasons why that practice is observed.

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Posted by BaltACD on Sunday, April 23, 2023 8:20 AM

Overmod
Among other things, the idle might adjust to raise coolant or oil temperature, or preclude exhaust deposits in the manifold, or when air compressors cut in.  I surmise this is not loadboxing or other engine testing, just standby of idle locomotives.

I suspect that bogie engineer can give you very good technical information for EMD engine control, and there are others (including Preston Cook) on RyPN who know how to find anything they don't already know.

A great deal of time and effort is involved in starting a shut-down prime mover, and arrangements might have to be made to fire up a Hotstart or other protection.  Not all these engines have proper prelubers, either.  It could be facile for a government or agency to think that extending a truck idling mandate to railroads would enhance pollution abatement -- a certain set of comments about smoke drifting across the road in Roseville comes to mind -- but they may not have watched enough cold engine starts...

I fall back on the tired old line 'railroads are concerned with the OR and idling cuts into that if properly considered... so there have to be reasons why that practice is observed.

The most common reason that a locomotive will not have its prime mover shut down when it is left to idle is that the locomotive has a bad battery set and if the prime mover is stopped it won't get restarted without outside assistance.

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Posted by bogie_engineer on Sunday, April 23, 2023 9:59 AM

There are several reasons not to shut an engine down. Ambient temperature and state of charge of the batteries are big ones. An EMD engine with good batteries won't spin fast enough to start if the ambient is below 40 degF as a general rule. SD60's in particular had trouble with worn valve seats that didn't hold enough compression to start unless spun faster than the starters could often manage. Really old engines can be notorious for head-to-liner seal water leaks that can cause hydraulic lock wnen started if the cylinder cocks aren't opened and the engine manually barred over to purge the water before attempting to start. Since the early '70s, EMD has had "creepy-crank" where the starters would spin the engine slowly before starting to detect a hydraulic lock without bending connecting rods. The pair of electric starter motors EMD has used since the introduction of AR10 alternator on the 40-series are upgraded Delco truck starter motors and are not famous for their reliability either. SD70ACe's use air starters that can spin the engine faster than the electric motors with improved reliability.

What you hear as the engine speed going up or down could be the air compressor periodically pumping up the air reservoirs. On all but a few recent EMD locos, the air compressor is shaft driven from the engine and an unloader valve prevents it pumping air until it's commanded - it's clearly audible when it's pumping at low idle engine speed and does sound "faster" than the engine idle noise.

An EMD engine at idle only burns about 4 gallons/hour so fuel consumption is not huge but automatic engine start-stop systems (AESS) are on all new locos and many have been retrofitted that shut down an idling engine and restart it based on ambient and water temperature, air reservoir pressure, and battery state of charge.

Dave

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Posted by PJS1 on Sunday, April 23, 2023 11:26 AM

Thanks to everyone for the insights. 

My perch is one of of the benches at the former Santa Fe Station that was moved from Moody, TX to Temple.  It houses the Temple Model Railroad Club.  The benches are on a raised platform facing the tracks and locomotive service facility.  It is a great place to watch trains.    

Rio Grande Valley, CFI,CFII

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Posted by SD70Dude on Sunday, April 23, 2023 1:44 PM

Every now and then the computer gives you little clues about why it's revving up.  

"Engine Speed Increase:  Turbo Cool-Down Cycle"

"Engine Speed Increase:  Air Compressor Operation"

"Load Limited:  Cold Engine"

Agree with Dave's comments about starting.  While I like the air starters, one downside of them is that the starting reservoirs can leak off if the unit remains shut down for a long time.  I'm sure they're designed to avoid this, but everything leaks eventually.  We are told to never manually shut down air start EMDs for fuel conservation, just leave them isolated (everything else is supposed to be shut down if we will be leaving it for more than 5 minutes).  Our SD70M-2s have also been fitted with backup electric starters as they cycle through shops for overhauls.  

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Posted by mvlandsw on Sunday, April 23, 2023 3:16 PM

Do the SD70s have separate air reservoirs dedicated to starting the diesel engine or do they use the main reservoirs for that purpose?

Mark

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Posted by bogie_engineer on Sunday, April 23, 2023 8:10 PM

The 70ACe's have a third reservoir dedicated for starting.

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Posted by zugmann on Sunday, April 23, 2023 9:09 PM

bogie_engineer
The 70ACe's have a third reservoir dedicated for starting.

Improvement over the 70M-2s. When they were new, they were notorious for not being able to start themselves if left sitting shut down.  Maybe they fixed that later - I wasn't around the newer stuff by then. 

But I still see AESS systems that will shut down an engine that isn't able to restart itself due to weak batteries. 

Or the GP40 we had with AESS that would go through 2 starters a year.   

 

Technology. 

  

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Posted by Overmod on Monday, April 24, 2023 10:00 AM

zugmann
Technology. 

Postwar technology, as Steve Slaby (one of my professors) liked to say -- often under his breath.

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Posted by PJS1 on Monday, April 24, 2023 10:16 AM

Here is another somewhat related question regarding the locomotives at the Temple locomotive service facility.  Well, loosely related!

At least three of the locomotives are remote control.  They are used in the yard north of Temple.  I believe the operator can control them from the ground.  If I am correct, how far can the operator be from the locomotive and maintain control of it?  Also, what happens if the operator's control mechanism fails?  

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Posted by Overmod on Monday, April 24, 2023 10:29 AM

PJS1
how far can the operator be from the locomotive and maintain control of it?  Also, what happens if the operator's control mechanism fails?  

We have a number of members who are qualified for RCO operation, and hopefully they'll give you accurate answers.

The technology purposely used a restricted range to prevent the temptation of remote operation 'out of sight of the train'.  If there is loss of sufficient signal, the locomotive goes to idle with the brakes applied.  Any of a fairly wide range of equipment failures will stop the remote, also.  The setup is purposely made somewhat clunky to wear and use, and as failsafe as designers could devise, for 'safety'.

Doesn't help the unwary, or the nonobservant, of course: for example, the recent death due to interfering collision with a dump truck would likely have occurred if the RCO engineer had been riding the point of the shove in that position.  

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Posted by zugmann on Monday, April 24, 2023 2:27 PM

PJS1
If I am correct, how far can the operator be from the locomotive and maintain control of it?  Also, what happens if the operator's control mechanism fails?  

Our yard was around 70 cars.  Other yards moved drafts of 100.  Depends on terrain and how good your box or the engine's antennas are. 

Our RCLs (remote controlled locomotive) could link up to 2 remote boxes.  They had to keep constant communication.  Even if the box that was linked up but not being used lost communication (say, the battery died), the RCL would come to a stop until you re-established communication. 

  

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Posted by jeffhergert on Saturday, April 29, 2023 4:25 AM

zugmann

 

 
PJS1
If I am correct, how far can the operator be from the locomotive and maintain control of it?  Also, what happens if the operator's control mechanism fails?  

 

Our yard was around 70 cars.  Other yards moved drafts of 100.  Depends on terrain and how good your box or the engine's antennas are. 

Our RCLs (remote controlled locomotive) could link up to 2 remote boxes.  They had to keep constant communication.  Even if the box that was linked up but not being used lost communication (say, the battery died), the RCL would come to a stop until you re-established communication. 

 

Or the battery falls out.

The yard I got to play with the RCLs they added repeaters to extend the range. That was after I went on to better things so I don't know how much the range was extended.

I still have my RCO vest in my locker.

Jeff

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Posted by oltmannd on Monday, September 25, 2023 4:26 PM

There's idle, low idle and low, low idle.  (roughly 315, 255 and 200 RPM for each, if memory serves)

You were likely hearing the unit go from low, low idle to idle.  

There's about a gallon an hour fuel difference between each of the idles.

-Don (Random stuff, mostly about trains - what else? http://blerfblog.blogspot.com/

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Posted by BDA on Sunday, October 1, 2023 5:41 PM

From my experience AESS is (was) a bit of a fad .

One of those things that sounds nice in candy land theory . Yes it can save fuel and reduce exhaust emissions but when the donk won't start when you need it to the locomotive can be effectively useless . Dramas can be batteries or no air or dodgy starter motors . I remember having a 70ACe and a Dash 9 shut down for service . The 70 couldn't crank fast enough to fire up so I started the D9 . I remember another driver telling me of a 70ACe that somehow hand grenaded its air starter so game over .

Best option I think is having air and electric start , probably ground air and electric supply at service facilities where possible . Our D9s have jump start cables and sockets to start one from another . It can also be used to get power into a lead unit if it fails in service . Provided you have sufficient trailing horsepower that cable gives you current for all control circuits brakes headlights markers comms etc . No AC inverter so no air con fridge probably kettle . 

 

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Posted by zugmann on Monday, October 2, 2023 1:28 PM

BDA
From my experience AESS is (was) a bit of a fad .

I don't think an engine built /rebuilt in the past 20 years doesn't have AESS.

 

It may be flawed at times (esp with dodgy batteries), but I don't think it qualifies as a fad.  

 

 

  

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Posted by BaltACD on Monday, October 2, 2023 4:20 PM

zugmann
 
BDA
From my experience AESS is (was) a bit of a fad . 

I don't think an engine built /rebuilt in the past 20 years doesn't have AESS.

It may be flawed at times (esp with dodgy batteries), but I don't think it qualifies as a fad.  

When I was still working - Fuel Conservation was the name of the game.  If a train was going to be held for over half an hour for a Train Meet or Pass, shut down all engines except one to keep air on the train.  In cold weather AESS allows this to happen without needing to drain the engines.

Since the price of fuel has only gone up since then - AESS is here to stay.

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Posted by bogie_engineer on Monday, October 2, 2023 7:46 PM

BaltACD

 

 
zugmann
 
BDA
From my experience AESS is (was) a bit of a fad . 

I don't think an engine built /rebuilt in the past 20 years doesn't have AESS.

It may be flawed at times (esp with dodgy batteries), but I don't think it qualifies as a fad.  

 

When I was still working - Fuel Conservation was the name of the game.  If a train was going to be held for over half an hour for a Train Meet or Pass, shut down all engines except one to keep air on the train.  In cold weather AESS allows this to happen without needing to drain the engines.

Since the price of fuel has only gone up since then - AESS is here to stay.

 

The Federal EPA requires all new locomotives built since 2012 to have AESS:

"In a 2008 rulemaking (73 Federal Register 37096), EPA set stricter emissions requirements for locomotive engines built or remanufactured after 2012. It also required new locomotives to be equipped with an automatic engine start/stop system (AESS) that will shut down the engine after 30 minutes of idling."

https://sgp.fas.org/crs/misc/IF10978.pdf

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