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Posted by Euclid on Monday, July 27, 2015 11:38 AM
schlimm
 
tdmidget
dmidget wrote the following post 9 hours ago: " However, the AAR claim is quite false, which discredits them as an accurate source of opinion." Has it occurred to you that the AAr and FRA might have different difinitions of accident?

 

Yes.  But the study I cited concerns causes of derailments only, not all accidents regardless of definition.   At best, the AAR statement is disingenuous in understating (I believe deliberately) with its <0.99% figure.  That said, brakes are not a major factor in derailments.  Poor track is.

However, ECP has many benefit not limited to safety.

 

ECP also has benefits to safety that the AAR is ignoring in their statistic on derailments related to braking, and its relationship to the benefits of ECP.
For example, when the AAR refers to the number of derailments caused by braking problems, they are NOT counting the derailments that are due to slack run-in, which could be prevented by ECP brakes.  They are also not counting derailments caused by UDEs, which could be prevented by ECP brakes.  They are also not counting derailments caused by poor train handling, which might have been prevented by ECP brakes. 
And the AAR is also not acknowledging the ECP benefit in quicker stopping that can mitigate the damage and spill by reducing the number cars in the pileup.
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Posted by BaltACD on Monday, July 27, 2015 11:48 AM

Euclid
schlimm
tdmidget

Yes.  But the study I cited concerns causes of derailments only, not all accidents regardless of definition.   At best, the AAR statement is disingenuous in understating (I believe deliberately) with its <0.99% figure.  That said, brakes are not a major factor in derailments.  Poor track is.

However, ECP has many benefit not limited to safety.

ECP also has benefits to safety that the AAR is ignoring in their statistic on derailments related to braking, and its relationship to the benefits of ECP.
For example, when the AAR refers to the number of derailments caused by braking problems, they are NOT counting the derailments that are due to slack run-in, which could be prevented by ECP brakes.  They are also not counting derailments caused by UDEs, which could be prevented by ECP brakes.  They are also not counting derailments caused by poor train handling, which might have been prevented by ECP brakes. 
And the AAR is also not acknowledging the ECP benefit in quicker stopping that can mitigate the damage and spill by reducing the number cars in the pileup.

Slack run in and out, is not normally associated with braking - it is associated with the engineer not properly handling the application and removal of power to the train.

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Posted by Euclid on Monday, July 27, 2015 12:16 PM
dehusman

 

 
Let’ say that somebody said this to you: “There is no safety benefit that ECP can add to oil trains. This is proven by the fact that none of the oil train derailments so far have had causes that ECP could prevent.” How would you reply to that statement?

My reply would be its a red herring and a misrepresentation of the argument. Nobody has said there is "no" benefit. There are just there are options that more effectively deter releases.

No, you said there is no benefit.  On page 29, you said this:
Please site specifically which OIL TRAIN derailments were cause by slack action or "lack of train handling precision". I'll save you the trouble, the answer is none.
Slack action problems will be in trains of mixed car types, in mixed loads and empties. Those problems are not found in unit trains like oil trains. Your bringing up "slack action" as a cause is the red herring.
********************************************
 
You say that NONE of the recent oil train derailments were caused by slack action.  Then you say that those slack action problems are not found in oil trains. 
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Posted by Wizlish on Monday, July 27, 2015 12:18 PM

BaltACD
Slack run in and out, is not normally associated with braking - it is associated with the engineer not properly handling the application and removal of power to the train.

The 'slack run-in' that is important to the present discussion is not 'associated with braking' in the sense the "AAR statistics" would consider it.  Again, it's the slack run-in that occurs after the derailment has technically occurred ... the derailment being the only thing that causes part of the train to decelerate more quickly than brakes can apply or, once applied, retard the trailing portion of the consist.  To my knowledge there are no FRA statistics that describe this as a contributing factor to accident severity, or that discriminate it from a derailment consequence of any other kind.I am not altogether sure that there could be meaningful data from which such statistics could be derived (in the absence of pervasive monitoring of train condition, for instance).

The points about UDEs and 'poor train handling' are better taken.  There can be little question that eliminating the former on HHFTs is desirable ... but isn't it better addressed by proper maintenance and adjustment of the relatively 'captive' HHFT consists?  And as noted (repeatedly, in multiple contexts) the pneumatic brake system per se plays a very small role in practical train handling.  It is true (also as noted repeatedly) that the use of an ECP system in train handling would allow many more options safely ... but we are not concerned with what could be done better, right now, only what shouldn't be done worse.

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Posted by Wizlish on Monday, July 27, 2015 12:27 PM

Euclid
You say that NONE of the recent oil train derailments were caused by slack action. Then you say that those slack action problems are not found in oil trains.

And this is supposed to be a problem ... how?

He said two things, both of which are objectively true:

None of the oil-train incidents were caused by slack action;

Slack action is unlikely to be an accident cause in 'unit-train' like consists, including those of existing forms of HHFT.

You seem to have confused what Dave is saying with what Don Oltmann said a few posts back (the latter being what has your bee in a bonnet regarding 'no benefit from ECP' to oil trains).  You're doing neither your case nor your credibility much good by barking up that wrong tree.

I confess I'm still looking to Don to qualify the statement he made.  Until he does that, the "discussion" about ECP is likely going to continue to be another song that doesn't end.  I say we wait for it.

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Posted by Euclid on Monday, July 27, 2015 12:44 PM
Wizlish
 
Euclid
You say that NONE of the recent oil train derailments were caused by slack action. Then you say that those slack action problems are not found in oil trains.

He said two things, both of which are objectively true:

None of the oil-train incidents were caused by slack action;

Slack action is unlikely to be an accident cause in 'unit-train' like consists, including those of existing forms of HHFT.

[my emphasis in red]

No, I am not talking about what Don Oltmand said.  I am talking about what Dave Husman said.  And no, he most certainly did NOT say, “Slack action is unlikely to be an accident cause in 'unit-train' like consists, including those of existing forms of HHFT,” as you say he did.   
What he said is, “Those problems [slack action that can cause derailments] are not found in unit trains like oil trains.”
On the previous page, he said “Nobody has said there is "no" benefit.”
On page 29, he said there is no benefit because the problem does not exist on oil trains.   
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Posted by flmiller on Monday, July 27, 2015 12:48 PM

Moderators,

Please, the horse is dead - now stop the beating.

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Posted by Wizlish on Monday, July 27, 2015 1:03 PM

Euclid
 
Wizlish
 
Euclid
You have to look at it in that context.
 
Well, rather than debate whether you should consider my point in its proper context, let me ask you a question.

I'll take up the question in a moment.  There is no 'debate' about your point in some 'proper context'.  What you did is the equivalent of 'here in my hand is a list of 205 known Communists' when there may, or may not, be Communists around at all.  And that is not acceptable whether or not you think you can justify the form by saying 'it didn't really matter if there was a number; it's just a hypothetical example for the sake of argument' or whatever.
Your point involves some percentage of oil-train accidents that ECP could either prevent or mitigate.  That is a good point, and deserves the level of discussion it's being given now.  We don't know the actual percentage of derailments to HHFT-like operations that ECP could 'prevent', although we are working our way toward getting a reasonable set of error bars around a range of numbers.  Once there, we can specialize more in determining the 'best' implementation of ECP, or perhaps some alternative technologies, that can reduce the hypothetical incidence of preventable derailments.  (I happen to think that will be far from 'enough' of an answer to serve as a basis for an ECP mandate, but I also think it's more than a little of a red herring in itself, so that's no reason to give up on investigating ECP technology, its capabilities, and what is claimed for it...)
Let’ say that somebody said this to you:  “There is no safety benefit that ECP can add to oil trains.  This is proven by the fact that none of the oil train derailments so far have had causes that ECP could prevent.”  How would you reply to that statement?
I would start by shaking my head in despair and quoting Ronald Reagan: "There you go again..."
Nothing, of course, can be "proven" by any 'fact' that events so far have not produced a particular outcome.  I have been over that particular fallacy several times with you and you don't listen, so I won't waste time on postequinocidal verberation again.  I repeat here that there are safety benefits that ECP can provide HHFTs, in a number of respects both actual and hypothetical, but I also repeat here that the prevention of worsening of a derailment during an emergency application is a small, if indeed technically meaningful, "benefit" over what conventional brakes provide in that situation.  And that the actual propensity of the air brake system to produce derailment causes directly in HHFTs is relatively small. and probably not worth the enormous cost in capital, compatibility, etc. that mandated use of ECP would entail.
Having repeated those things, I would listen carefully for something other than a mere rebuttal, or a 'yes, but...' restatement of previous mistaken or misconstrued points.  I might have to listen for a protracted time.  I might listen in vain.
 
This reason not to apply ECP to oil trains has been given more than once here in this thread, and it is also the position of the AAR.
 
To the extent that either of those points, as presented, is actually the position of the AAR, I think it reflects politics far more than objective assessment.  Anyone sane recognizes that handling of oil trains will be 'safer' in many respects if ECP brakes were fitted.  But that is not the question here, which is the actual, predictable-with-high-confidence elimination of fireball explosions to HHFTs.  And anyone sane recognizes that ECP brakes, at tremendous cost and (so far) somewhat dangerous incompatibility with the 'rest' of the air-braked equipment in service on American railroads, are only peripherally 'solutions' to most of the actual, observed incidents that cause the fireballs.  At Lac Megantic, for example, connecting an eight-dollar switch on the locomotive -- that, I believe, came set up from the GE factory -- would have set the train air when the independent fell below a level still adequate to hold the train to controllable speed, and setting the air would have stopped and held the train short of the disaster.  Do the cost/benefit on that vs. mandated ECP, which of course would have stopped the accident eight ways from Sunday, but again more 'by accident' than through the conscious use of the ECP system's capabilities.
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Posted by schlimm on Monday, July 27, 2015 1:35 PM

A meta-comment.  There are several issues that have been confounded into a mess: ECPs, ECTs, causes of derailments and economics (the bottom-line variety).  This is compounded by a paucity of relevant statistics and an abundance of opinions posing as facts.  Ick!

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Posted by richg1998 on Monday, July 27, 2015 1:47 PM

flmiller

Moderators,

Please, the horse is dead - now stop the beating.

 

Many children are like that. lol

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Posted by BaltACD on Monday, July 27, 2015 1:59 PM

flmiller

Moderators,

Please, the horse is dead - now stop the beating.

 

This is and has been since its inception, the dead horse thread!  If we didn't have dead horses, dinosaurs and albatross' to beat what fun would there be.  

Set them up and knock them down!

Just like bowling with bits and bytes!  The horse needs another 60 lashes to get to 1000

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Posted by Wizlish on Monday, July 27, 2015 2:08 PM

BaltACD
This is and has been since its inception, the dead horse thread! If we didn't have dead horses, dinosaurs and albatross' to beat what fun would there be.

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Posted by Euclid on Monday, July 27, 2015 2:15 PM
Wizlish,
What on earth are you talking about?  You say you won’t consider what I said in its proper context.  Then you make up a context for me which concludes that what I said about a hypothetical number is equivalent to a list of 205 Communists.  Yikes. 
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Posted by Wizlish on Monday, July 27, 2015 2:17 PM

Analogy is wasted on the 'historically challenged'.

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Posted by Euclid on Monday, July 27, 2015 2:18 PM
tree68
 
Wizlish
As noted earlier, the only real 'safe' thing to do is keep the cars from leaving the clearance envelope of the track they are on ... either by not deraiiing in the first place, or by staying reasonably upright and in line, off adjacent tracks, and away from lineside things to run into and puncture.

 

Curiously, a former DOT official seems to agree with you:

 
What can railroads do to prevent accidents?

 

Brigham McCown, a former head of the federal agency that regulates rail transport of hazardous materials, said an array of new technologies patented within the last decade can warn of defects and identify trouble spots before accidents happen.

 

For example, sensors can be put on the lead locomotive to measure rail thickness, detect deformities and alert engineers, he said. Sensors can also be placed under track or next to rail ties to detect movement in track beds, or on cars to detect a broken wheel, he said.

 

"Given the sheer volume of hazardous materials and crude oil, we simply can't afford to have these rail cars come off the track," McCown said.

Read more: http://www.businessinsider.com/heres-why-so-many-oil-trains-have-derailed-this-year-2015-3#ixzz3h5t78TQ4

Is it logical to have sensors on every locomotive that measure thickness and find flaws?  Or is it better to just run dedicated detector vehicles frequently enough to detect developing rail problems before they cause trouble?
A sensor in the track bed to monitor alignment sounds like a good idea.  How many sensors would be needed for every mile of track?
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Posted by Norm48327 on Monday, July 27, 2015 2:33 PM

BaltACD

 

 

This is and has been since its inception, the dead horse thread!  If we didn't have dead horses, dinosaurs and albatross' to beat what fun would there be.  

Set them up and knock them down!

Just like bowling with bits and bytes!  The horse needs another 60 lashes to get to 1000

 

But Bucky is an expert at resurecting deceased equines. Zzz

Norm


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Posted by Wizlish on Monday, July 27, 2015 2:38 PM

Euclid
Is it logical to have sensors on every locomotive that measure thickness and find flaws? Or is it better to just run dedicated detector vehicles frequently enough to detect developing rail problems before they cause trouble?

I think the sensible answer is 'both', as the two approaches do different things. 

Even with fast modern multicore processors, there's a limit to how much you can read at high speed, and how quickly you can react to anything bad you find.  I suspect you are also thinking about the cost of equipping all the relevant locomotives, or a meaningful 'enough' subset, with the appropriate equipment.

On the other hand, if there is sun kink, or a broken rail or failing weld, or dragged-equipment damage, or a host of other problems, no frequency of detector-car or hi-rail runs would work to catch it.  McCown notes in this context that if the locomotive catches the problem, there is just that much more time to stop the train under control before the problem worsens, or one of the car trucks derails.  By extension there is more time to calculate a choice of responses, and to be able to benefit from the full set of advantages of something like ECP braking.

That does not substitute for the detector-car runs.  Those would involve a much more intensive suite of sensors, perhaps with distributed processing and analysis, and in my opinion this specific 'mission' is the first place we would see 'autonomous vehicles' in use on the railroads: relatively inexpensive and light vehicles capable of getting on and off tracks in ways that safely avoid traffic or any other 'hazard' associated with modern railroading.

 

A sensor in the track bed to monitor alignment sounds like a good idea. How many sensors would be needed for every mile of track?

There is something of a 'catch' here in that measuring alignment in the track, rather than via something moving on that track, is likely to be more difficult and expensive, and calibrating many of the logical ways to implement the measurement may be difficult.

Having said that, there are certainly forms of monitoring -- standing-wave ultrasonics in runs of CWR and 'structured light' across railheads or complex structure might be examples -- that would give you an indication from the track if certain forms of damage or displacement of line and surface were occurring.   I believe we have had several posts that describe how often 'acoustic' sensors (presently set to look for problems such as bad bearings or dragging equipment on cars) should be placed in track -- I'd think that geometry sensors might easily share the same spacing (for commonalty of data connection to the cloud if nothing else) with additional sensors located at critical areas such as 'tuned' bridge or grade-crossing transitions.

This is its own rather interesting discussion, and you might consider starting a separate thread to discuss it more specifically.

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Posted by Euclid on Tuesday, July 28, 2015 10:07 AM

jeffhergert

Euclid,

I don't know where I've read it, someones's link on these threads or just looking on my own at various sites, but some of the claims have been reduced fuel consumption, longer wheel and brake shoe life.  To get all the benefits, you have to use the brakes.  Using them you would think it would reduce wheel and brake shoe wear and increase fuel usage.  You are after all, power braking.  Possibly because of quicker reaction time and being able to modulate the brake application easier than conventional brakes it might give those benefits.

Jeff,
I too have heard the claims about reduced fuel consumption and reduced wheel and brake shoe wear.  My understanding is that these benefits are claimed to result from eliminating the need for power braking.
The FRA Booz-Allen-Hamilton Final Report of 2006 describes it this way:
Elimination of power braking is also feasible. Under conventional technology, when braking for a reduced speed area ahead, such as a curve or switch, the locomotive engineer may have to apply more brake effort than is required, and slow down far ahead of the speed restriction. The engineer cannot release the brakes because he may not be able to recharge the reservoirs in time to safely negotiate the restriction, so he applies locomotive power while the brakes are applied, in order to optimize his speed (i.e., power braking). This is both a waste of fuel as well as unnecessary wearing of the brakes, as well as possible wheel damage, as they fight the locomotive pull. With graduated release, the engineer could simply reduce the braking force in order to optimize speed.

 

 

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Posted by BaltACD on Tuesday, July 28, 2015 11:54 AM

Euclid
jeffhergert

Euclid,

I don't know where I've read it, someones's link on these threads or just looking on my own at various sites, but some of the claims have been reduced fuel consumption, longer wheel and brake shoe life.  To get all the benefits, you have to use the brakes.  Using them you would think it would reduce wheel and brake shoe wear and increase fuel usage.  You are after all, power braking.  Possibly because of quicker reaction time and being able to modulate the brake application easier than conventional brakes it might give those benefits.

 

Jeff,
I too have heard the claims about reduced fuel consumption and reduced wheel and brake shoe wear.  My understanding is that these benefits are claimed to result from eliminating the need for power braking.
The FRA Booz-Allen-Hamilton Final Report of 2006 describes it this way:
Elimination of power braking is also feasible. Under conventional technology, when braking for a reduced speed area ahead, such as a curve or switch, the locomotive engineer may have to apply more brake effort than is required, and slow down far ahead of the speed restriction. The engineer cannot release the brakes because he may not be able to recharge the reservoirs in time to safely negotiate the restriction, so he applies locomotive power while the brakes are applied, in order to optimize his speed (i.e., power braking). This is both a waste of fuel as well as unnecessary wearing of the brakes, as well as possible wheel damage, as they fight the locomotive pull. With graduated release, the engineer could simply reduce the braking force in order to optimize speed.

Can't speak to other carriers, on mine power braking has been effectively banned for a decade or more.  The primary form of train speed modulation is Dynamic Braking that is supplemented with air braking only when necessary. 

While Engineers can instruct EIT (Engineers in Training) on the methods necessary to perform Power Braking, the Senior Road Foreman of Engines must be notified so that the Engineer doing the Power Braking won't be disciplined for doing it.

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Posted by Wizlish on Tuesday, July 28, 2015 11:59 AM

Euclid
The FRA Booz-Allen-Hamilton Final Report of 2006 describes it this way: Elimination of power braking is also feasible. Under conventional technology, when braking for a reduced speed area ahead, such as a curve or switch, the locomotive engineer may have to apply more brake effort than is required, and slow down far ahead of the speed restriction. The engineer cannot release the brakes because he may not be able to recharge the reservoirs in time to safely negotiate the restriction, so he applies locomotive power while the brakes are applied, in order to optimize his speed (i.e., power braking). This is both a waste of fuel as well as unnecessary wearing of the brakes, as well as possible wheel damage, as they fight the locomotive pull. With graduated release, the engineer could simply reduce the braking force in order to optimize speed.

Don't we have to distinguish 'power braking' (notch 5-8, which is illegal on most roads, and should be) from stretch braking in lower notches for better 'precision train handling' (at one time weren't there stickers about that?)

A certainly 'thinkable' improvement to ECP would be the ability to do graduated release either valve-by-valve (probably under full computer control) or in different parts of a consist, thereby reducing the need for even small amounts of stretch braking. 

I don't think there is any question that proportional graduated release and prompt reapplication is both safer and better, in and of itself.  What I wonder is how potentially dangerous it is during a 'transition era' between triples and ECP, for some of the same 'people' reasons that depending on dynamic for train control on some critical grades is not currently advisable.  I can easily see how an engineman 'used' to graduated release will get into trouble when he gets a consist with conventional brake response and then finds at some point, usually critical, he can't reduce his set without a full release and following lag...

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Posted by Euclid on Tuesday, July 28, 2015 12:56 PM
I am not sure what to conclude about the point about power braking being illegal.  Was this the case in 2006 when the FRA report said ECP would eliminate the need for power braking?
My only point was in responding to Jeff’s question about reduced wheel and brake shoe wear.  Earlier, he mentioned that the claims of ECP salesmen stating a reduction of wheel wear, brake shoe wear, and fuel consumption seemed counterintuitive. 
Actually, I am not sure I understand his point because he seems to equate the reduction in wheel and brake shoe wear with power braking.  And in that sense, a claim of reduced fuel consumption seems counterintuitive because power braking uses more fuel. 
On the other hand, the FRA report says the reduction of wheel and brake shoe wear results from eliminating power braking because ECP eliminates the need for it.    
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Posted by tree68 on Tuesday, July 28, 2015 1:12 PM

Euclid
I am not sure what to conclude about the point about power braking being illegal. 

What you should conclude is that you're reading way too much into it.

As Balt indicated, the policy on his road (ie, train handling rules) has made power braking a prohibited practice for some years now.  

There is no law prohibiting power braking - the policy/rule is that of the individual railroad(s).  They certainly have their reasons, and I'm sure most of them have already been enumerated here.

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Posted by Euclid on Tuesday, July 28, 2015 2:34 PM

tree68
 
Euclid
I am not sure what to conclude about the point about power braking being illegal. 

 

What you should conclude is that you're reading way too much into it.

As Balt indicated, the policy on his road (ie, train handling rules) has made power braking a prohibited practice for some years now.  

There is no law prohibiting power braking - the policy/rule is that of the individual railroad(s).  They certainly have their reasons, and I'm sure most of them have already been enumerated here.

 

I am not reading anything into it.  I was only responding to Jeff Hergert's comments a couple pages ago.  Also when I referred to power braking being "illegal," I did not mean in terms of actual law.

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Posted by Wizlish on Tuesday, July 28, 2015 10:08 PM

Sorry, I was the one who used the word 'illegal' to refer to power braking in notch 5 and above.  I meant it in the sense that you'll Hear From The Railroad if they catch you doing it (and apparently there are people on some railroads who actually download the telemetry from the locomotives and check to see if the throttle was in a 'prohibited' run, even for a few seconds, with the brake applied...)

Euclid
Actually, I am not sure I understand his point because he seems to equate the reduction in wheel and brake shoe wear with power braking. And in that sense, a claim of reduced fuel consumption seems counterintuitive because power braking uses more fuel....

I am not quite sure how you got this confused, but review a few of the points from previous postings here and relevantly elsewhere:

Jeff and others have noted that most train handling is done with the throttle and dynamics, and to a lesser extent with the independent (straight) brake which acts on the same axles as the dynamic.  The Westinghouse train brake is only used when absolutely required, and ideally only when the train is to be brought to a physical stop or run consistently downhill (as for example on a downgrade steep enough that a failure of dynamics will not hold the train below the critical speed where compositon brakeshoe fade eliminates the ability to stop, between about 22 and 25 mph).

There are some cases where 'precision train handling' through sags and some other kinds of feature will benefit from, or even require, a little stretch braking (probably no more than notch 2 or 3; there are postings about where and how this is appropriate).  I am not sure if there are situations where standards-compliant ECP systems wouldn't achieve the same result as light stretch braking, but Jeff and some of the other good engineers here will tell you straight if you ask them.

Yes, there will be some saving in brakeshoe and foundation wear if ECP features (particularly the ability to do repeated light sets and graduated release, much as if you could control the train brakes with a standard road-vehicle brake pedal) substitute for the need to stretch brake a consist that has been given a 'set' that's unsafe to running release.  I happen to think this is on a par with the AT&T 'where's my big savings?' as it would reflect only a light amount of retardation for only a few percent of actual running hours, or time that the air brakes actually needed to be utilized in train handling.

Yes, I'd give careful thought to enhancing ECP with the ability to modulate brakes on individual cars or sections of a consist -- this is essentially the same functionality that would enable practical differential braking, so you have synergistic reasons to provide that capability now.

 

On the other hand, the FRA report says the reduction of wheel and brake shoe wear results from eliminating power braking because ECP eliminates the need for it.

Good as far as it goes.  But again this is the contrapositive of the 'where's my big savings?' -- where's ny great safety advantage when it only applies a small part of the time, to only a select few situations where special conditions in train dynamics may prevail only some of the time.  I think people are being a bit sophistic with the actual results observable from the tech.  But I could be wrong, and we have people reading this thread with the specific distinctive technical competence to know.

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Posted by Euclid on Tuesday, July 28, 2015 11:41 PM
Wizlish
Euclid
Actually, I am not sure I understand his point because he seems to equate the reduction in wheel and brake shoe wear with power braking. And in that sense, a claim of reduced fuel consumption seems counterintuitive because power braking uses more fuel....

Well to be very clear, this is what I am not sure if I understand about Jeff’s comment.  Here is his comment quoted in red, with my points of my failure to understand parts inserted in blue.  I understand all the points made about using dynamic versus air in other paragraphs and posts:
“Euclid,
I don't know where I've read it, someone’s link on these threads or just looking on my own at various sites, but some of the claims have been reduced fuel consumption, longer wheel and brake shoe life. [I assume this refers to ECP brakes rather than dynamic since this follows our discussion in which Jeff mentioned some of the claimed ECP benefits seem counterintuitive, and I asked him what he meant by that] To get all the benefits, you have to use the brakes. Using them you would think it would reduce wheel and brake shoe wear and increase fuel usage. [Why would using the brakes reduce wheel and brake shoe wear?  Why would it increase fuel usage?] You are after all, power braking. [Why would using the brakes necessarily mean using them in power braking?] Possibly because of quicker reaction time and being able to modulate the brake application easier than conventional brakes it might give those benefits.
I would think that using the ECP for braking would increase wheel and brake shoe wear compared to not using them for braking, and have no effect on fuel consumption.  But using the ECP brakes eliminates the need for power braking, and not using power braking would reduce wheel and brake shoe wear and also reduce fuel consumption.  Jeff seems to suggest that the ECP brakes will include power braking when he says about using them, “You are after all, power braking.”  Why would power braking be a necessary component of ECP braking?  The FRA paper says that ECP eliminates the need for power braking. 
So those are the points that I am not sure I understand as well as the reasons why I am not sure. 
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Posted by Wizlish on Wednesday, July 29, 2015 12:38 AM

[quote user="Euclid"]I don't know where I've read it, someone’s link on these threads or just looking on my own at various sites, but some of the claims [for ECP] have been reduced fuel consumption, longer wheel and brake shoe life. [I assume this refers to ECP brakes rather than dynamic since this follows our discussion in which Jeff mentioned some of the claimed ECP benefits seem counterintuitive, and I asked him what he meant by that]

This refers to ECP vs. conventional triple-valve air.

Think of dynamic as being a replacement for ANY kind of air brake whenever it can be used.

Conventional air brakes, because of the way they work, can't be released in any way other than full release (by pumping up the trainline pressure and waiting for the valves to release).  So you can go from light to heavier to heavier application of the brakes, but any time you want to 'go back' you have to go all the way back to no brakes applied, and stay there for a while, before you can start applying them again.

Standards-compliant ECP keeps the trainline constantly charged for all 'service' applications, so there is always pressure available to be valved into the brake cylinders at any time.  Conversely the electric valves allow any degree of release of brake-cylinder pressure.  I don't know if there is any formal time lag between commanded set and commanded release (in other words, the time it takes between air being valved into a brake cylinder to air being exhausted from it) but I would suspect it is very short, on the order of seconds at most.

[quote]To get all the benefits, you have to use the brakes. Using them you would think it would reduce wheel and brake shoe wear and increase fuel usage. [Why would using the brakes reduce wheel and brake shoe wear? Why would it increase fuel usage?]

Again, what Jeff was saying is that to get the touted 'benefits' of ECP, you have to be actually using the train air brakes in train handling, rather than controlling the train with throttle, dynamic, and straight air (as he, and I, have been saying).  Again, the 'reduction' in wear' and 'fuel savings' come from the use of ECP for train handling at the times you use the air brake for train handling, compared to the use of triple-valve air where you need to use stretch braking to get slack control.  You need to use the stretch braking because you can't release whatever set you've applied without having to wait, but you need to have the brakes applied at some point sooner than it will take to do a running release and then reapplication.  Naturally when you have to pull the train against the applied brakes, you will get additional shoe and tread wear, you will consume additional fuel, you have an increased risk of derailment, etc. 

Simply put, the ECP allows you to control how much brake you have, both with modulated application and modulated release, with relatively low latency, and with assurance that the proportional valve application and release will occur essentially simultaneously in every car in the train. 

If you are handling the train successfully with momentum, throttle, and dynamic, you don't get into the air at all. That obviously saves you wear and tear on the train brakes, as you never apply them in the first place.  At this point you might want to remember that dynamic braking also reduces shoe wear on the power too, and to the extent associated with shoe friction it reduces treadwear somewhat, but the 'fuel savings' is not as straightforward as you might think because many locomotives need to be kept throttled up for technical reasons associated with the way the dynamic braking is implemented.

When he said 'increase fuel usage' I was pretty sure he meant something like 'increase fuel-usage economy' or 'improve fuel usage'.  But he can qualify that for you himself when he reads this.  It should be possible to calculate the sfc for a train of particular characteristics in dynamic vs. using modulated ECP braking for the same effect (net of any electricity or compressor power from the engines needed to run the ECP system), and likewise possible to determine whether the cost of shoe and tread wear, etc. from using the ECP brakes is higher than the fuel burn and other costs from using the dynamic.

[quote]You are after all, power braking. [Why would using the brakes necessarily mean using them in power braking?]

See the previous point about having to keep brakes applied in some situations, and therefore having to use stretch or power braking to keep the train moving against that set as part of necessary train handling.

I think you may be confusing the point of the 'power braking' with the actual use of the brakes for retardation.  Only very small amounts of stretch braking (to keep the slack out of the train when making speed changes over undulating profiles or when traversing trackwork like crossovers that put drag or deceleration on some parts of the consist but not others, for example) are necessary if the brakes can be worked proportionally in both application and release.  Train crews would be delighted to be able to dispense with the 'braking' part of most notch-5-or-higher "power braking" -- and ECP graduated release would allow them to do just that.  The 'braking' in question, again, is an artifact of how triple valves and single-pipe actuation works, and while it is a necessary evil to get the benefit of single-pipe air-only automatic action, it is still an evil from a train-handling perspective.  We could probably coin a more descriptive term for the practice, like 'dragging the consist with non-safely-releasable set', that points out it's not 'braking' but the opposite that we're actually doing with the power.  I invite you to come up with such a term if it will help your understanding to do so.

Possibly because of quicker reaction time and being able to modulate the brake application easier than conventional brakes it might give those benefits.

In this context, it is mostly the ability to modulate the release, both in terms of graduated reduction and the ability to reapply without going through a full release, that are of importance here.  The quicker 'reaction time' (presumably you mean due to simultaneous electric application vs. having to wait for the sonic signal to propagate down the trainline to set the triples) is not particularly important in application (except transiently), and of course since the 'reaction' is so very different between conventional and ECP, it almost makes no sense to compare them other than to note how gross and slow the functional release is for the former compared to the latter.

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Posted by oltmannd on Wednesday, July 29, 2015 6:26 AM

Most of the reasons I thought of when I said that many benefits of ECP touted by the FRA don't apply to unit trains have already been discussed here.  Primarily....

Tuning w.r.t. load/empty:  Problems with train handling and derailments from UDEs + train makeup can be helped quite a bit with ECP.  Unit trains don't have any long car/short car issues and are much less likely to generate L/Vs of sufficient maginitude to derail trains from emergency brake applications.

This is the biggie.

The reason RRs are applying ECP to unit trains to test is not that they see huge benefits, it's just that it's the easiest service to test.  Captive equipment, ability to keep power with the train, relatively few numbers of T&E and mechanical train, etc, etc.

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

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Posted by oltmannd on Wednesday, July 29, 2015 6:49 AM

Wizlish
In this context, it is mostly the ability to modulate the release, both in terms of graduated reduction and the ability to reapply without going through a full release, that are of importance here.

I'm not sure graduated release is a 'great to have' feature of ECP.  Stretch braking has pretty much been extinguished as an approved method of train handling in the name of fuel economy.  No need to worry about the slack action on the caboose...

The immediate benefits of ECP are kind of mediocre - somewhat better braking.  The latent benefit that comes from putting smarts and communication on freight cars, combined with other technology is what might transform railroads.

The problems with getting, good, reliable intercar connectors - even in unit train service where you're not messing with them much - is a pretty big hurdle the FRA and NTSB have chosen to ignore.  The RRs haven't done themselves any favors either, with their relatively slow and back-burner approach to testing ECP.  Now, they're stuck aguing against a rule with finger of blame for slow development pointed at themselves.

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

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Posted by Euclid on Wednesday, July 29, 2015 8:37 AM
Wizlish,
I understand those points that you make above about what Jeff said.  My only confusion is about what he said apparently indicating things like the use of air brakes reducing wheel and brake shoe wear and reducing fuel consumption.  I agree that he must have been referring to dynamic brakes at that point because the reduced wear and fuel use would be the benefits of dynamic braking.  But if the reference meant dynamic braking, then it conflicts with other parts of the statement to the extent that it is a continuation of a context established in an earlier post by Jeff and my question back to him.
I think the gist of where this started is with Jeff wondering how ECP could reduce wheel wear, brake shoe wear, and fuel consumption.  The FRA report says the reason is that ECP eliminates the need for “power braking.”  So that was my response to Jeff’s question.    
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Posted by Euclid on Wednesday, July 29, 2015 8:40 AM
Here is an interesting tank car:
 
I wonder what engineering reasoning drives the design of this type of tank car, which is apparently used in Russia.  It looks modern enough, but it is surprising that they use a separate frame with the tank lashed into place with straps.  I wonder if those are loose wooden cushions that are laid into the tank saddles and cradle the tank.  Or perhaps they are steel channels welded to the tank in order to spread the loading out there to more of the tank wall.
I like how the side ladder seems to give the illusion of melting right into the side of the tank about half way up.  Actually, the ladder terminates and is replaced by two independent steps welded directly to the tank.  The feature must be intended to limit the overall width of the car.  That red wheel under the side must be the handbrake.   

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