Let's use a run that sees a .6 percent grade as the steepest grade on the line.
For different types of trains, how much power would you guys typically have and how much of it are you allowed to use? Is Trip Op mandatory to use?
Priority Intermodal -
Normal Intermodal -
Freight -
Bulk Trains (Oil, grain, potash, sand, ...)
On CN, Trip Op is mandatory. They run a lot of freight and bulk trains at .5 hpt and even as low as .3 and .4 with solid consists of AC power. Intermodal, even their high priotorty trains, are often around 1.0 hpt and sometimes are even throttle restricted.
It is a regular occurance to have to isolate units and/or be throttle restricted on the power that you have.
To have excessive power and be allowed to use it is a rare occurance and a treat when it does happen.
For the other guys on here from different roads, how do these values compare to your territories of .6 ruling grades.
10000 feet and no dynamics? Today is going to be a good day ...
My carrier is tonnage based - Maximum allowed tonnage for a train is based on
1. Bulk Commodity trains - the tonnage rating of 2 GE AC's + 1 GE dash 8.2. General Mercandise - the tonnage rating of 3 GE dash 8's.3. Intermodal - 3 units - normally GE Evo DC's - Intermodal is limited to 12000 feet and 11000 tons.
All tonnage ratings are based on the ruling grade in the route of the train - not just to the next terminal. Manned helpers are used when required. Horsepower per ton is calculated, but is not used in the decision making process.
Never too old to have a happy childhood!
See the several pertinent pages at Al Krug's "RR Facts and Figures" website:
http://www.alkrug.vcn.com/rrfacts/rrfacts.htm
especially "Horsepower vs Tractive Effort":
http://www.alkrug.vcn.com/rrfacts/hp_te.htm
- Paul North.
I think you guys are missing his question. He's not asking how much power you need for a particular train, but more like how much power they allow you to use. I'm sensing some frustration over fuel conservation practices?
I'm guessing Trip Op is GE's Trip Optimizer? We don't have it on my territory. We do have NYAB's Leader and EMD's Smart Consist. (Some of the newest EMDs have both, but there is a bug that currently won't allow both systems to work at the same time. So we are to use the Leader, if it's working.) Not using it without an acceptable reason risks getting discipline.
We don't use HP/Ton anymore, but rather Tons Per Axle using Equivalent Powered Axle ratings. The lower the priority, the more tons per axle are allowed. Our paperwork (usually) shows which engines to have on line or isolated/shut down. Using an engine that is shown to be isol/shut down requires filling out an on-line report as to why and if it was requested by the crew or dispatcher. (The crew is to avoid stalling or because of mechanical failure, etc. The dispatcher is to allow the train to make better speed, keeping things fluid.) We have a fuel desk that will call trains and ask if they have one of the fuel managment systems engaged or if they have an engine shown isol/shut down on the paperwork on line. Big Brother is indeed watching.
They just allow most trains to use enough power to get over the road. I've had 4 or 5 engines in the consist, but only allowed to use 1 or 2. Might get you up to 30mph on the flat parts, depending on train of course. Some engineers in those instances will ask if they can put another on line. (It used to be for awhile that dispatchers and corridor managers couldn't authorize another engine just to allow a train to make track speed. I read a report where they let trains die on HOS just because they wouldn't let them turn on another unit to pull the mountains faster than 10mph. Now they can authorize using more power.) I'll be glad to use more power if they tell me to, but I won't ask. I'm all for giving them what they want. Sometimes that's the only way to get them to see that some of their ideas aren't as good in actual practice compared to how they appear on paper.
We also have current instructions for empty coal or grain trains to run a DP consist no higher than notch 4. Empty grain trains running conventionally can only use one engine on line. Empty coal trains running conventionally can have two engines on line.
For trains with authorized maximum speeds above 50 mph, our rules have a throttle 5 restriction above 50 mph. (Some subdivisions have the throttle restriction beginning at 40 mph for loaded/empty bulk commodity trains.) It's often voided to priority intermodal or those running late according to their service schedule.
Jeff
jeffhergertHe's not asking how much power you need for a particular train, but more like how much power they allow you to use.
Isn't 21st Century railroading fun? Certainly not how it was done on the mainline between Calgary and Winnipeg in my Dad's time. Interesting thread.
Bruce
So shovel the coal, let this rattler roll.
"A Train is a Place Going Somewhere" CP Rail Public Timetable
"O. S. Irricana"
. . . __ . ______
jeffhergert I think you guys are missing his question. He's not asking how much power you need for a particular train, but more like how much power they allow you to use. I'm sensing some frustration over fuel conservation practices? ... Jeff
...
Suspect you misread my response - maximum tonnage and maximum power allowed on line go hand in hand. While a train may have upto 12 units in the engine consist, the maximum number allowed on line are what I stated. 2 AC's + dash-8 on bulk trains and 3 dash-8's or their equivalent in other trains.
When I worked for Conrail we were only allowed to have 24
traction motors on line. Anymore and you would pull out
drawbars.
BaltACDWhile a train may have upto 12 units in the engine consist, the maximum number allowed on line are what I stated.
It's always kind of disappointing to see a train with a boatload of power on the head end, only to realize that only 2 or 3 are actually working, and the rest are simply (for all intents and purposes) boxcars...
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 can only speak of CP in the US of about 3-4 years ago. Things may have changed.
I can't really answer the OP directly so I'll just make a series of generalities.
Trains were given only enough power to get them over the ruling grade for the entire length of it's journey. Extra power was being deadheaded and was not to be used. So, the power planners or the roundhouse foreman would take the tonnage of the train, look at the timetable for the minimum horsepower required for each subdivision it was to cover and scramble some combination of GE AC 4400's or SD40's or SD60's, or even geeps. While two 60's could almost equal two 4400's, it definitely took 3 SD40's.
Trip Optimizer was being adopted back then so I'm guessing it's required now.
All trains were limited to notch 2 over 45mph, unless you were "Expedited", and that was noted on your train list. Dispatchers could upgrade you to Expedited (60mph max), as they weren't really militant about it back then. But, I only saw dispatchers upgrading the trains who were unexpedited only because they were running on a weekend and thus didn't have a set, tightly controlled destination arrival time. In other words, same power, same type of train, like autoracks, for example.
Our hottest expedited intermodal trains would still only ever get 2 AC4400's, so there's plenty of places where you're never going to see 60mph. And, CP loved running those 12,000 ton Eastbound mostly loaded manifest trains with one AC4400.
As for requesting to put units on the line, or using discretion to put them on the line to make better speed, that all depends on how you're being paid. If it's an overtime run, then who am I to deny CP all the fuel savings it deserves? On the other hand, if it's a long ID run then sure, the quicker you get there, the quicker you get home!
tree68 BaltACD While a train may have upto 12 units in the engine consist, the maximum number allowed on line are what I stated. It's always kind of disappointing to see a train with a boatload of power on the head end, only to realize that only 2 or 3 are actually working, and the rest are simply (for all intents and purposes) boxcars...
BaltACD While a train may have upto 12 units in the engine consist, the maximum number allowed on line are what I stated.
She who has no signature! cinscocom-tmw
nyc#25 When I worked for Conrail we were only allowed to have 24 traction motors on line. Anymore and you would pull out drawbars.
Kind of a silly reasoning (but that is RR reasoning). Around here it is now 27 equivalent online* (3 AC motors). You're not going to pull out a drawhead unless you do something stupid. Still can't shove with more than 16, though. Which means you can't even use 2 AC motors. And remote jobs are only allowed a paltry 12 either way.
*-there are exceptions for bulk commodity trains. I think you can go as high as 32.
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
We don't have any throttle limitations in regards to train speed. HPT is the only thing that they go by when calculating throttle restrictions or notch limitations. I don't think they even know what adhesion or tractive effort is.
Our axle limitations are as follows:
We have a restriction of 24 powered axles in a consist, 30 on a unit train if you get permission. 18 axles of dynamic brake or 12 axles if there is an AC traction unit in the consist.
On my first post, in regards to a train operating on a territory with .6% as the steepest grade, we commonly run 2 units conventional up to 15000 or sometimes even 16000 tons and 3 units with one being a mid train DP at 25000 tons. HPT .5 or even .4 with solid AC traction.
My heaviest conventional train was almost 18000 tons with 4 units. Almost a solid bulk train.
They have run 26000 ton DP trains on a regular basis and I must say they run run quite well.
Train lengths are long. 14000 foot intermodal with DP (only 1 train from Toronto to Winnipeg), they do run up to 12000 feet conventional.
11000 foot loaded mixed and bulk trains with DP and conventional when empty with same footage.
The restrictions that are route/train symbol/subdivision specific will have the grade baked into them already.
Dave H. Painted side goes up. My website : wnbranch.com
ndbprrHasn't all this discussion ignored a needed piece of information namely the length of the grade and total elevation change?
I think not, and here is why: The whole idea of a 'ruling grade' is to determine the point at which it will be the most difficult to restart a stopped train, or the point at which maximal power will be required by the locomotives (perhaps net of momentum in some circumstances) to keep it moving effectively within the technical constraints of the motive power. Almost by definition, at any other points on the grade, the power will be adequate to start the train or keep it moving, so no 'adjustment' of car factors or power consists is required -- assuming the wrong assumptions about things like hourly rating or sustained developed horsepower from prime movers have not been made.
If you were talking about fuel capacity (and perhaps its associated mass or provisioning cost) then the length and sustained grade profiles would be significant. But that is not what determines the locomotives that are required to be under power in a particular consist. And of course a long grade (and its associated cumulative elevation change) -- or even a sawtooth profile that results in a much higher net "elevation change" in the sense that locomotives had to burn fuel to pull the load up many sequential hills without being able to regenerate any of that power on the downhills -- just involves more fuel.*
Yes, there is an 'elevation'-related concern: at higher altitudes there is less oxygen in a given volume of ambient air, so unless there is some provision to adjust the turbocharger, the available horsepower will drop off. Same is true on hot days when the charge air is less dense and at the same time more resistant to compression. But a good car-factor formula back in Ralph Johnson's day included these kinds of effects, and I would find it hard to believe that modern bean-counting ones that are sophisticated enough to track diesel-engine parameters in realtime would not do so.
*I happen to think that it would make sense to be able to take locomotives on and off the line dynamically, in realtime, as a kind of larger equivalent of proper genset-locomotive operation, in those cases where more than the minimum number of locomotives is not needed all the time. There are many reasons why this is not the most reliable way to run things, including the many situations under which an engine taken offline on the road might fail to start or load again when needed. I have read a number of threads here and elsewhere that describe this.
Our community is FREE to join. To participate you must either login or register for an account.