[quote user="Overmod"]I continue to believe that the actual dangerous component in diesel PM is nanoparticulates, which no commercially viable DPF can catch /quote]
I agree. Nanoparticles (0.1–10 μm) are a real danger to health.
https://www.frontiersin.org/articles/10.3389/frsc.2021.690444/full
It's actually the other way around. The ONLY reason DEF would be increased on any engine with a DPF is to knock down the added nitrogen oxide introduced by the cheap 'regeneration' expedient -- wasting up to about 6% excess fuel to burn out the 'soot' trapped in that moronic filter before it clogs and ends the parade. No filter = no excess fuel, no uncontrolled catalyzed combustion, no flames out the stack... no extra nitrogen oxide generation, and no need for extra DEF or the relatively fast control loop needed to preclude ammonia slip from regen.
It would not terribly surprise me to find some enginaster who would try to combine the functions of the SCR and a particulate filter, but that won't work right either from the operability of the selective nitrogen-reduction catalyst or doing regen in the presence of that catalyst.
I continue to believe that the actual dangerous component in diesel PM is nanoparticulates, which no commercially viable DPF can catch and likely no effective regeneration cycle using richened exhaust would be likely to eliminate from a filter architecture that could catch.
But take combustion peak temp up and increase duration and you inherently limit creation of PM in the first place, at the cost of higher NO... which the DEF system will knock down with relatively small additional DEF mass flow using the same control architecture and operation.
The other half of PM control is to limit rapid changes in engine speed, and prevent additional fueling to accelerate the engine between governed 'notches' while under load. Both these things are trivial on a diesel-electric locomotive, and vanish if even a small hybrid battery capacity is provided.
I hate to tell you this bit if EMD is thinking about using a Def system then it will always have a DPF as part of the system. Why because that's were the Def is injected into during the regeneration process to reduce the emissions of the engine. Some Def is always being injected to keep the emissions lowered but when the filter plugs up look out for your paint jobs. You think a turbocharger get hot. The normal temperature of a DPF that's regenerating is around 1800 degrees. They've literally burned trucks to the ground and set pavement on fire during these things.
SD70Dude I've never had the opportunity to ride or run one of the EMD Tier-IV units, but I do have a story that seems relevant to this conversation. CN had been testing a pair of EMD demonstrators (EMDX 1605 and 1606) through 2017. They got good reviews from crews but the test period abruptly ended after both units (on different trains) failed out on the road in a -40 Saskatchewan winter's night. Less than a week later CN placed an order with GE for 200 new units, this order was later increased to 260. A short time later our head ESO (Engine Service Officer, that's Canadianese for Road Foreman) went for a ride on my train, and we took the opportunity to quiz him about the new locomotive purchases. He said that the EMD Tier-IV units used too much fuel and replacement parts were more expensive than GE stuff, and the enroute failures were just the icing on CN's decision to continue buying GEs. I should note that early production ET44ACs and everything built at the Fort Worth plant during its first year or two seemed to have A LOT of problems, far more than just the higher fuel consumption of EGR engines. The computers would crash all the time, air lines and wires would break off, and plenty of little stuff like light switches would snap if you so much as brushed it. Just poor build quality all around. But I have to admit our GEVO fleet seems to have been pretty reliable over the last couple years, either they or our mechanical department must have done a pretty good job at tracking down and fixing the problems.
I've never had the opportunity to ride or run one of the EMD Tier-IV units, but I do have a story that seems relevant to this conversation.
CN had been testing a pair of EMD demonstrators (EMDX 1605 and 1606) through 2017. They got good reviews from crews but the test period abruptly ended after both units (on different trains) failed out on the road in a -40 Saskatchewan winter's night. Less than a week later CN placed an order with GE for 200 new units, this order was later increased to 260.
A short time later our head ESO (Engine Service Officer, that's Canadianese for Road Foreman) went for a ride on my train, and we took the opportunity to quiz him about the new locomotive purchases. He said that the EMD Tier-IV units used too much fuel and replacement parts were more expensive than GE stuff, and the enroute failures were just the icing on CN's decision to continue buying GEs.
I should note that early production ET44ACs and everything built at the Fort Worth plant during its first year or two seemed to have A LOT of problems, far more than just the higher fuel consumption of EGR engines. The computers would crash all the time, air lines and wires would break off, and plenty of little stuff like light switches would snap if you so much as brushed it. Just poor build quality all around.
But I have to admit our GEVO fleet seems to have been pretty reliable over the last couple years, either they or our mechanical department must have done a pretty good job at tracking down and fixing the problems.
If Progress Rail can eliminate that DPF that may help with fuel economy. As DPF's have to burn fuel to regen.
Government never has a recession. Taxes continue to be collected regardless. Government passenger agencies are in expansion mode and have the cash to spend on capital equipment and Siemens has very adroitly tapped in to that revenue stream. Good for them!
2021 could be the first year since the Great Depression where no new locomotive orders are placed. The only new locomotives being built this year were part of multi-year production orders from before the Pandemic. By that I mean by Class I carriers for North American use.
I would hope so . 70ACe is realistically a 9043 with the bugs ironed out .
Leo_Ames For what it's worth, I've seen over a half dozen engineers praise these from their standpoint. Smooth running locomotives with comfortable and very quiet cabs. But they're of course not the ones deciding what locomotives are purchased.
For what it's worth, I've seen over a half dozen engineers praise these from their standpoint. Smooth running locomotives with comfortable and very quiet cabs.
But they're of course not the ones deciding what locomotives are purchased.
If I never had another EMD SD70ACe variant again, I wouldn't be sad. That goes for the T-4s as well. I will say they're better, somewhat, than those SD9043s UP has/had.
Jeff
caldreamer When a new locomotive is being tested on a railroad do the "BRASS HATS" that make the desisions as to which locomotive to purchase get extensive feed back from the people in the field? For example the engineers and people who maintain them to get a good idea as to running quality and reliability.
When a new locomotive is being tested on a railroad do the "BRASS HATS" that make the desisions as to which locomotive to purchase get extensive feed back from the people in the field? For example the engineers and people who maintain them to get a good idea as to running quality and reliability.
Only in a perfect world. Otherwise all the influences above board and below come into play. Some awful decisions come into play. Look at the various abandoments that proved ill advised.
Don't forget PSR's impact of doing less with less.
Lots of older C44-9Ws still in service as well.
It doesn't look like a run away sucess from a sales point of view but IMO Tier 4 spec locomoties were set up to fail .
Between Odrama legislating ridiculous emissions standards and the operators refusing to go with DEF , the purchase and running costs were never going to be acceptable .
When there is a vast pool of used power that can easily and more cheaply be overhauled this is the way to go .
The need to achieve Tier 4 emissions compliance has forced much complication onto the builders , and the complexity pretty much leads to high failure rates which is not acceptable in the real world .
So to answer the question is the 70ACeT4 a failure I tend to say no because it achived T4 compliance . I think the issue is that the T4 standard is the failure because it's not something that can be cost effectively achieved in the real world .
Leo_AmesFor what it's worth, I've seen over a half dozen engineers praise these from their standpoint. Smooth running locomotives with comfortable and very quiet cabs. But they're of course not the ones deciding what locomotives are purchased.
Additionally, the people manipulating the controls of a locomotive are not the once that calculate and react to the economic success or failure of the locomotives.
Never too old to have a happy childhood!
In the interest of being fair, Volker's specific point was the 1010J was "Not a success" which I would consider an even harder thing to pinpoint.
Part of the evidence being the lack of interest in it for Marine uses.
This was also in the context of the news that Cat is partnering with Chevron to convert the 710 to run on Hydrogen. I want to be clear that I didn't post this hear to be negative towards anyone, I just wanted to see the thoughts of this group of people for my own edification and felt it only right to attribute it to the person who is a poster here.
I'm not sure if there re advantages to a 2 stroke vs. a 4 stroke with regards to a Hydrogen application.
Greetings from Alberta
-an Articulate Malcontent
Product A sold a thousand units and product B sold 10. A is a success.
Product A is "bad-word-placed-here" and product B is stunningly wonderful. B is a success.
You guys aren't agreeing on terms, and then there's the "yes, but..." part.
There can be more than one definition of success. For the same product.
The definition(s) should be MEANINGFUL.
They should be defined, as opposed to "fluffy". Maybe "strictly defined".
They should be able to be evaluated, usually with numbers.
So. The GE was a success because it sold well.
Was it a also a success because it produced a net profit per unit?
Maybe the EMD has a better mean-time-between-failure. This would be IT'S the success. By this definition.
"Fallen on hard times" is awfully tough to include in the above.
You two guys should be thrashing out the definition of "success", as it applies to railroad locomtives. Once you both agree, or have complimentary definitions (he grudgingly accepting yours--you grudgingly accepting his), THEN start applying it/them to locomotives. Not the other way 'round.
Ed
On another website, occasional poster Volker took it as a given that the SD70ACe-T4 was a failure for Cat/EMD.
I disagreed with his reasoning, but thought it might be interesting to get the view here.
His logic was that based on units sold, the EMD T4 must be viewed as a failure, but I felt that was simply not a nuanced view of the locomotive. GE got their T4 unit out in 2012, Production EMD T4 first rolled out at the end of 2016. That's 4 years that GE had to work out kinks and rack up sales.
At the time in 2016, railroads seemed to be buying Tier 4 almost for the privledge of being able to by T4C units and then as T4C unit sales tapered off, you saw everybody looking to revitalize older units from the SD90->SD70ACU programs to MACe to Dash-9 to AC rebuilds. New T4 units dropped off a cliff for both builders as the railroads started rebuilding things.
And then we were thrown into a traffic down turn combined with aggressive PSR. Motive power requirements dropped. The final straw being that the T4 units by design are less fuel efficient. Which the railroads wouldn't be thrilled with even during periods of cheap fuel.
So, to me, it feels like it would be hard to judge the quality or operational success of the SD70-T4 by units built.
And that's to say nothing of the legacy baggage EMD has with it's changing hands, stagnation and lower production ability compared to Wabtec.
Curious if anyone thinks I have this wrong and that in fact the ACe-T4 is not a success.
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