Could some of the action/ motion that Ulrich describes be caused by the (anti) wheel slip control of the locomotive ?
- PDN.
Considering that todays trains are nominally from one to two and a half miles long - what one sees at the head end of the train is not necessarily the condition the engineer is modulating his throttle for - it may be a sag or knoll that is being enountered well back in the body of the train - far from the viewer.
Gradients that a idividual's eyes and senses cannot see are easily seen and felt by a locomotive engineer and his engine consist with a 15K ton two mile train. A train that the engineer is trying to both move and control the slack that is contained in the train - slack that can tear the train apart if not controlled.
Never too old to have a happy childhood!
Looks like they're saying it helps to take slack when the train is stopped, and you're trying to start it. That was true in steam days, and maybe it still is.
Once the train is rolling, the only way to accelerate it (on the level) is to pull on it. Quit pulling on it, and let the slack roll in, and the train quits accelerating.
timz Ulrich I'm guessing that's what's going on.. i.e. using slack/train's momentum to best advantage to accelerate the train. Only way to let the slack run in (on the level) is to reduce the engine's pull. Why would doing that make the train accelerate better? If the engine quits pulling the train, and allows the train to nudge it, then the engine is slowing the train.
Ulrich I'm guessing that's what's going on.. i.e. using slack/train's momentum to best advantage to accelerate the train.
Only way to let the slack run in (on the level) is to reduce the engine's pull. Why would doing that make the train accelerate better? If the engine quits pulling the train, and allows the train to nudge it, then the engine is slowing the train.
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It's been fun. But it isn't much fun anymore. Signing off for now.
The opinions expressed here represent my own and not those of my employer, any other railroad, company, or person.t fun any
UlrichI'm guessing that's what's going on.. i.e. using slack/train's momentum to best advantage to accelerate the train.
I think you'll find that the engineer isn't really backing off the throttle to gain slack so much as adjusting the throttle to fit what he/she sees on the ammeter/traction meter.
Ideally, you want a constant pull. Otherwise you chance pull-aparts.
Recall that on older EMD's, advancing a notch gains you an increase in RPM over what it should be. The RPMs then drop a bit. Don't know why, but they do.
Larry Resident Microferroequinologist (at least at my house) Everyone goes home; Safety begins with you My Opinion. Standard Disclaimers Apply. No Expiration Date Come ride the rails with me! There's one thing about humility - the moment you think you've got it, you've lost it...
I guess that where the engineer's "feel" of the train comes in... once the train has achieved a nominal speed of say 2mph he/she reduces the throttle and speed to allow the slack to run in ever so gently before once again opening up the throttle. And so on until the train is up to track speed. Based on what I'm hearing as a bystander at trackside, I'm guessing that's what's going on.. i.e. using slack/train's momentum to best advantage to accelerate the train.
Oops. No way to delete.
Thanks to Chris / CopCarSS for my avatar.
jeffhergertWe had an engineer once start out on an ascending grade (from a crew change point) on a coal train like that. He had an engine with an electronic air brake control. They operate the same and look like (although maybe slightly more compact than) their mechanical brothers. About the only difference is the handles seem to be stiff when moving them. There is a "stop" at the minimum service position. When releasing an application, sometimes that position can fool you into thinking you've moved the handle all the way to release when you haven't. This is what apparently happened to this engineer. He was in notch 8 when he realized this and moved the handle all the way to release. The train, at least the knuckle that broke, did not like his method of starting. I don't think the conductor, nor the MOP (Manager of Operating Practices, other places known as a Road Foreman or Travelling Engineer) who downloaded the event recorder did either. When starting a train with power I watch the load meter (either, depending on how it's equiped, the ammeter or tractive effort indicator) and wait for it to stabilize or slightly drop back before taking another notch. When first starting watch the ground (that's why there is a light underneath the cab at night) for movement, watch the EOT (if equipped) for signs of movement and how air is coming up on the rear end. Be a bit wary of the EOT when first getting on the train. I've had some that don't register until you're up to 15MPH or more, and on a long slinky train it may start moving but there can still be some slack adjusting. This is where your butt, and the "feel" of the train, come into play. On those long ones, make sure you stop feeling those little tugs before coming out too much on the throttle. Jeff
We had an engineer that was sarting a heavy slop freight on an ascending grade. He had 3 engines, and was sitting at a stop signal. Well, the trailing two auto-shut down. When you go to move again, it takes ~30 seconds for an engine to restart itself, plus another minute or so until it will start loading. Engineer didn't take this into consideration, and tried to tug the train right away. He was in a high notch, barely moving (if moving at all) when the trailing engines came to life. Yeah, broke the train in half.
timzSlack in, then slack out, then slack in, then out...why would that be a better way to accelerate the train?
You don't want the slack crashing in and out, you just want to keep a nice, steady, and slow speed to start out. Throttle manipulation let's you achieve that goal. You don't want to have the head end taking off at 10mph when the rear end hasn't even started moving.
JPS1 Jeff, thanks for the excellent discussion of Leader, etc.
timz Ulrich Once the train is up to about 2 mph they ease up on the throttle, thereby allowing the slack to run in,giving the engines a nice little shove. They rinse and repeat the process until the train is up to track speed. Pretty smart way to do it... Slack in, then slack out, then slack in, then out...why would that be a better way to accelerate the train?
Ulrich Once the train is up to about 2 mph they ease up on the throttle, thereby allowing the slack to run in,giving the engines a nice little shove. They rinse and repeat the process until the train is up to track speed. Pretty smart way to do it...
Slack in, then slack out, then slack in, then out...why would that be a better way to accelerate the train?
You must have missed mvlandsw's response two entries back.
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"A stranger's just a friend you ain't met yet." --- Dave Gardner
UlrichOnce the train is up to about 2 mph they ease up on the throttle, thereby allowing the slack to run in,giving the engines a nice little shove. They rinse and repeat the process until the train is up to track speed. Pretty smart way to do it...
tree68 Ulrich Other engineers (I'd say they're in the minority) simply open up the throttle and let it go.. Hence the term "eight and sand" (which I think is the nom de fora of one of our posters here). I don't have the luxury of playing with slack - not that there's a lot of slack in four or so coaches - I'm carrying passengers. A smooth start is key, and I'll stay on the power until I'm approaching my desired speed. That doesn't mean I'm in notch 8 from the get-go, though. One notch at a time, settle in, take another...
Ulrich Other engineers (I'd say they're in the minority) simply open up the throttle and let it go..
Hence the term "eight and sand" (which I think is the nom de fora of one of our posters here).
I don't have the luxury of playing with slack - not that there's a lot of slack in four or so coaches - I'm carrying passengers. A smooth start is key, and I'll stay on the power until I'm approaching my desired speed. That doesn't mean I'm in notch 8 from the get-go, though. One notch at a time, settle in, take another...
When starting a train with power I watch the load meter (either, depending on how it's equiped, the ammeter or tractive effort indicator) and wait for it to stabilize or slightly drop back before taking another notch. When first starting watch the ground (that's why there is a light underneath the cab at night) for movement, watch the EOT (if equipped) for signs of movement and how air is coming up on the rear end. Be a bit wary of the EOT when first getting on the train. I've had some that don't register until you're up to 15MPH or more, and on a long slinky train it may start moving but there can still be some slack adjusting. This is where your butt, and the "feel" of the train, come into play. On those long ones, make sure you stop feeling those little tugs before coming out too much on the throttle.
Jeff
Ulrich From my observation standing at trackside, some engineers seem to remember their HS physics and/or have an intuitive understanding of the Law of Conservation of Momentum. Once the train is up to about 2 mph they ease up on the throttle, thereby allowing the slack to run in,giving the engines a nice little shove. They rinse and repeat the process until the train is up to track speed. Pretty smart way to do it, and I wonder if that's taught or if they somehow figure it out on the job. Other engineers (I'd say they're in the minority) simply open up the throttle and let it go.. sometimes one sees the wheels slip and alot of sparking, suggesting that using the train's momentum to one's advantage is the better way to go. The reason for reducing the throttle after the train starts to move is not to let the slack run in. Doing that would likely result in broken knuckles or drawbars when the throttle is opened again. The throttle is reduced to prevent moving the head end too fast before the rear end begins to move. If the slack runs in after the train has begun to move the throttle was reduced too much.
From my observation standing at trackside, some engineers seem to remember their HS physics and/or have an intuitive understanding of the Law of Conservation of Momentum. Once the train is up to about 2 mph they ease up on the throttle, thereby allowing the slack to run in,giving the engines a nice little shove. They rinse and repeat the process until the train is up to track speed. Pretty smart way to do it, and I wonder if that's taught or if they somehow figure it out on the job. Other engineers (I'd say they're in the minority) simply open up the throttle and let it go.. sometimes one sees the wheels slip and alot of sparking, suggesting that using the train's momentum to one's advantage is the better way to go.
UlrichOther engineers (I'd say they're in the minority) simply open up the throttle and let it go..
Jeff, thanks for the excellent discussion of Leader, etc.
Rio Grande Valley, CFI,CFII
JPS1 BaltACD JPS1 BaltACD Can't speak for all carriers, mine had Train Handling Rules that goverened how fast a throttle could be advanced - all of those rules were based on getting the entirety of the train moving - once the train was moving it was in the hands of the Engineer (or the 'engineer surrogate' programs of EMD or GE depending on the power on the head end). What is an engineer surrogate program? How does it work? EMD's is known as Leader; GE's is known as Trip Optimizer. When crews take charge of their locomotive consist they identify the to the locomotives software the territory they will be operating as well as the pertinent details of their train (loads, empties, tonnage, type of train). Once the train is in motion the surrogate will then (to my knowledge - AND I AM NOT AN ENGINEER) take over operation of the train while it is opeating on CLEAR signals or proper block authority in Dark territory. The engineer can take back control at anytime when he views it is necessary to comply with a less than CLEAR signal indication or any other reason. Use of these surrogate programs is encouraged by the company, and their use is checked by company officials when data from locomotives is downloaded for further review. The company's position is that the use of these programs saves fuel in the operation of trains when compared to fully engineer controlled. I am sure the Engineers that participate in this forum have much more accurate and detailed explanations of these systems. Sounds a bit like an auto-pilot on the airplanes that I have flown?
BaltACD JPS1 BaltACD Can't speak for all carriers, mine had Train Handling Rules that goverened how fast a throttle could be advanced - all of those rules were based on getting the entirety of the train moving - once the train was moving it was in the hands of the Engineer (or the 'engineer surrogate' programs of EMD or GE depending on the power on the head end). What is an engineer surrogate program? How does it work? EMD's is known as Leader; GE's is known as Trip Optimizer. When crews take charge of their locomotive consist they identify the to the locomotives software the territory they will be operating as well as the pertinent details of their train (loads, empties, tonnage, type of train). Once the train is in motion the surrogate will then (to my knowledge - AND I AM NOT AN ENGINEER) take over operation of the train while it is opeating on CLEAR signals or proper block authority in Dark territory. The engineer can take back control at anytime when he views it is necessary to comply with a less than CLEAR signal indication or any other reason. Use of these surrogate programs is encouraged by the company, and their use is checked by company officials when data from locomotives is downloaded for further review. The company's position is that the use of these programs saves fuel in the operation of trains when compared to fully engineer controlled. I am sure the Engineers that participate in this forum have much more accurate and detailed explanations of these systems.
JPS1 BaltACD Can't speak for all carriers, mine had Train Handling Rules that goverened how fast a throttle could be advanced - all of those rules were based on getting the entirety of the train moving - once the train was moving it was in the hands of the Engineer (or the 'engineer surrogate' programs of EMD or GE depending on the power on the head end). What is an engineer surrogate program? How does it work?
BaltACD Can't speak for all carriers, mine had Train Handling Rules that goverened how fast a throttle could be advanced - all of those rules were based on getting the entirety of the train moving - once the train was moving it was in the hands of the Engineer (or the 'engineer surrogate' programs of EMD or GE depending on the power on the head end).
Can't speak for all carriers, mine had Train Handling Rules that goverened how fast a throttle could be advanced - all of those rules were based on getting the entirety of the train moving - once the train was moving it was in the hands of the Engineer (or the 'engineer surrogate' programs of EMD or GE depending on the power on the head end).
What is an engineer surrogate program? How does it work?
EMD's is known as Leader; GE's is known as Trip Optimizer.
When crews take charge of their locomotive consist they identify the to the locomotives software the territory they will be operating as well as the pertinent details of their train (loads, empties, tonnage, type of train). Once the train is in motion the surrogate will then (to my knowledge - AND I AM NOT AN ENGINEER) take over operation of the train while it is opeating on CLEAR signals or proper block authority in Dark territory. The engineer can take back control at anytime when he views it is necessary to comply with a less than CLEAR signal indication or any other reason. Use of these surrogate programs is encouraged by the company, and their use is checked by company officials when data from locomotives is downloaded for further review. The company's position is that the use of these programs saves fuel in the operation of trains when compared to fully engineer controlled.
I am sure the Engineers that participate in this forum have much more accurate and detailed explanations of these systems.
Sounds a bit like an auto-pilot on the airplanes that I have flown?
LEADER is by New York Air Brake Co. Trip Optimizer is by GE. Trip Optimizer is a better, but not perfect operating system. A third energy management system is EMD's Smart Consist.
LEADER has two versions. The first version only prompts the engineer to make throttle or dynamic brake adjustments. The second and newer version (I believe this is the one alluded to in the advertisement on the back of Trains Magazine March issue. I know it makes me chuckle.) actually works the throttle and dynamic brake, like a form of automatic pilot. It is slightly better than the first version because the first version only prompts control of the lead consist, dpu consists are to be operated in sync with the lead. The second version will run the dp separately from the head end which allows for somewhat better train handling. Both versions have all permanent and current temporary speed restrictions for a given territory when logged into. Any unforseen temporary restrictions have to be handled manually. Once engaged it operates the train (automatically or by prompting the engineer) for the trip. Like Balt said, it's a Clear Block system. It doesn't know restrictive signals or limits of authority. It works good on some trains, not so good on others. On the display screen it predicts speed up to a few miles ahead. It seems like it is always calculating to the point that it takes action to avoid being over max speed 3 miles away and then realizes it's way under speed. Makes a lot more throttle adjustments than in necessary in most cases. Both versions if allowed to will tear trains up. (I know it got me a knuckle 80 cars deep on a dpu coal train. It was deemed a "mechanical failure" because I was following the LEADER program.)
Trip Optimizer has always been an automatic throttle/dynamic brake control system. It functions a lot like the LEADER second version. (Both TO and both LEADER versions can also prompt automatic air brake applications and releases.) Only it is better. I've been told the algorithems used by Trip Optimizer will be used for PTC operation. The LEADER screen is close to what the PTC display will look like from what I've seen in PTC screen mock-ups.
Smart Consist doesn't operate or prompt operation. Rather it operates with up to two trailing engines in a consist. It transfers loads between units for a given throttle setting and speed "to give the required power in the most fuel efficient manner". Nothing like having the lead engine go to idle and transfer the load to trailing engine(s). Unless you have a consist monitor system (newer engines have them) you don't know how the other engines are loading. When I'm running a train there are certain inputs I use. One is "feel" or the seat of the pants. Another is watching the load meter (ammeter on older engines, tractive effort indicator on newer ones) and listening to how the prime mover is sounding. Smart Consist, without a consist monitor, removes two of the inputs. It even affects the seat of the pants since the idle lead engine feels the slight bumps and tugs from the working units behind it. Smart Consist can work in conjunction with LEADER and Trip Optimizer.
We currently have all three systems. Use is mandatory when it is in working order, except for when running on unforseen or less than clear block situations. In my opinion Trip Optimizer is best, but my last trip (on a coal train) with it there were a few places where I felt I could do a better job. I was getting some slack action where I shouldn't have and we were approaching locations where I know it (and LEADER) have torn trains up.
LEADER's best feature is the display. It's better than Trip Optimizer's and can be zoomed in/out. (Both have a grade profile and a moving train on it. You can always see where you are at in relation to the topography.) Where manual control is required, we lose the screen. (If it's supposed to be a job aid, why do we lose the most important and best thing the system has?) Trip Optimizer just gives you a gray zone above the affected track diagram, but you don't lose the display. It was announced at a union meeting last year that the railroad may bring suit against NYAB because it hasn't delivered the promised savings.
Smart Consist (in my opinion) is junk. It has been tweaked and is a little better, but I don't think it is ever wise to have the lead engine in a consist go to idle. It would be better if it just ran the trainling units. If the program feels that one engine can be throttled down and still meet power requirements, it should be a trailing unit not the lead. When logging in to SC, you have a list of models from both EMD and GE to choose from so it "knows" what the locomotives are. As one would expect the GE list is more basic while EMD's has more variations for a specific model. The EMD list goes back far enough to include GP-9 models.
JPS1Sounds a bit like an auto-pilot on the airplanes that I have flown?
ChuckCobleigh BaltACD Engineers are the original slackers! But they're an interesting bunch.
BaltACD Engineers are the original slackers!
But they're an interesting bunch.
I see what you did there....
BaltACDEngineers are the original slackers!
Engineers are the original slackers!
Balt, that was b-a-a-a-d!
tree68 Each time the engineer bunched, then stretched the train, there was a resounding "bangbangbangbang" up and down the consist.
My memory of that sound was as a young (16 yr old) kid with my dads car, driving in Cincinnati near the produce terminals on the tracks near the Ohio river waterfront between two rows of ice type refrigerator cars and the train to my right started up with that BANG..BANG right outside my window. It reverberated off the cars to my left. Thought I had had it.. I wasn't going fast and it was a public area but it left an indelible memory.
I've told the story before, but here goes -
I grew up alongside what is now the CSX Saginaw Sub in Milford, Michigan. There's a bit of a grade there, and a curve that is apparently to be feared.
Happened upon a train of hoppers (don't recall if empty or full, and couldn't see the locomotives or caboose, so don't know which way they were headed, although I'd guess north) that was stalled. This was back in the day of friction bearings.
Starting a train with friction bearings often included bunching the slack before pulling it back out, so only one car was started in motion at a time. For a hundred car train, that might involve some 200' of slack, more or less.
Which explains the slack action in the caboose.
It took several tries to get the train rolling again. Each time the engineer bunched, then stretched the train, there was a resounding "bangbangbangbang" up and down the consist.
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