BigJimWell, that is your mind talking, not the mechanical dept. Can you prove that even a 73' centerbeam was in the derailment?
17 years in Conrail Mechanical Department - staff engineering position. Did a lot of locomotive application work, some derailment analysis work and testing.
-Don (Random stuff, mostly about trains - what else? http://blerfblog.blogspot.com/)
So, did you amend the rule book/timetable to limit trailing tonnage on said car?
.
oltmanndYou ever had a full tonnage train with three 4000 HP locomotives running in notch 8 at 10 mph on a 9 degree curve with an 80' empty head out? Where and when?
oltmannd All weather adhesion rating for AC units is around 35%. For DC units with computer based wheel creep control, about 27-28%. Non-wheel creep (Dash 2, 7 Series), 18-21%.
All weather adhesion rating for AC units is around 35%. For DC units with computer based wheel creep control, about 27-28%. Non-wheel creep (Dash 2, 7 Series), 18-21%.
The 18-21% is in line with the 16% dispatchable factor adhesion given in the 1968 MR article on grades with a bit better control. The 35% available with AC could be done with DC motors with separately excited field windings and pole face windings, but motors with these features would be more like the traction motors in the PRR DD1's.
One other figure from the 60's was a 33% factor of adhesion for the KM desel hydraulics, with the combination of smooth torque and the three axles on a truck running off a common Cardan shaft. Demonstrator testing of the U25B's gave a 25% factor of adhesion on clean dry "western" rail. Durng one dynamometer test, the GE Little Joe demonstrator achieved 35% factor of adhesion - I've seen a few comments about traction current enhancing adhesion by burning away contaminants.
You want to dispatch trains on what you can count on, day in and day out.
BigJim So, did you amend the rule book/timetable to limit trailing tonnage on said car?
Yes. Headed axle limit on trains ascending HSC w/o helpers. Also tonnage limit.
oltmannd BigJim So, did you amend the rule book/timetable to limit trailing tonnage on said car? Yes. Headed axle limit on trains ascending HSC w/o helpers. Also tonnage limit.
Looks like NS 'forgot' your instructions. Oops.
Greetings from Alberta
-an Articulate Malcontent
SD70Dude oltmannd BigJim So, did you amend the rule book/timetable to limit trailing tonnage on said car? Yes. Headed axle limit on trains ascending HSC w/o helpers. Also tonnage limit. Looks like NS 'forgot' your instructions. Oops.
NS forgot their Institutional Knowledge from those they let go putting in PSR.
Never too old to have a happy childhood!
Excerpt from CSX Baltimore Division Timetable in 2015
CSX Batltimore Division Timetable No. 1 April 1, 2015 4466 PLACING EMPTY CARS IN TRAINS Empty Car Placement Train Classification Instructions for Manifest Trains: Empty cars 80 feet and longer (other than a box car) must be placed in the train in such a location that the trailing tonnage behind these empty cars does not exceed the amount listed below. In territory where helper locomotives are used on the rear of the train, their tonnage rating should be subtracted to the trailing tonnage listed below when determining the location for the restricted car(s): Between Direction TonnageHyndman & Sand Patch Westward 3,500Connellsville & Sand Patch Eastward 5,100Connellsville & New Castle Eastward & Westward 13,300
4466 PLACING EMPTY CARS IN TRAINS
Empty Car Placement Train Classification Instructions for Manifest Trains:
Empty cars 80 feet and longer (other than a box car) must be placed in the train in such a location that the trailing tonnage behind these empty cars does not exceed the amount listed below. In territory where helper locomotives are used on the rear of the train, their tonnage rating should be subtracted to the trailing tonnage listed below when determining the location for the restricted car(s):
Between Direction TonnageHyndman & Sand Patch Westward 3,500Connellsville & Sand Patch Eastward 5,100Connellsville & New Castle Eastward & Westward 13,300
BigJim
BigJim oltmannd BigJim So, did you amend the rule book/timetable to limit trailing tonnage on said car? Yes. Headed axle limit on trains ascending HSC w/o helpers. Also tonnage limit. Was this before or after the fact? And, what particular rule number and tonnage rating? I ask because as I have said before, in my time there was no restrictions on centerbeam flat cars.
Was this before or after the fact? And, what particular rule number and tonnage rating? I ask because as I have said before, in my time there was no restrictions on centerbeam flat cars.
If there were only two unit on line and the train was pushed from the rear, the derailment doesn't occur. Car length becomes irrelevant.
Wonder what the superelevation is -- maybe 2 inches? Think that has much effect?
(The 2008 chart says four inches -- page 34 of the PDF)
http://multimodalways.org/docs/railroads/companies/NS/NS%20Track%20Charts/NS%20Pgh%20Division%20Track%20Chart%202008.pdf
What was the tonnage?
timz Wonder what the superelevation is -- maybe 2 inches? Think that has much effect? (The 2008 chart says four inches -- page 34 of the PDF) http://multimodalways.org/docs/railroads/companies/NS/NS%20Track%20Charts/NS%20Pgh%20Division%20Track%20Chart%202008.pdf What was the tonnage?
Probably still four inches. That'll help things along a bit. Tonnage around 8000? 140+ cars? Train resistance balanced out at ~10 mph
Just to add some physics details to the issue. What keeps trains on the track is the ratio of lateral to vertical force. Lateral is velocity squared/radius toward the outside of the curve and pulling times the sine of the car angles for pull inside the curve. Vertical is gravity. Safe speeds are designed to keep L/V less that 0.5 and some specify less than 0.3. The accident in Seattle last year exceeded L/V to about 1.0 and the train flew off the track. Stringlining occurs when the pull of the locomotive at the curve angle exceeds the gravity pull.
petitnj Stringlining occurs when the pull of the locomotive at the curve angle exceeds the gravity pull.
Which even my "back of the envelope" calculation showed is what likely happened.
Getting to L/V is tougher to do and you can't reasonably determine it for every car in every location under every possible circumstance. There are trains built and run that will just plain derail if the go into emergency at the right spot. But, they don't, so no news is good news...
oltmannd Which even my "back of the envelope" calculation showed is what likely happened. Getting to L/V is tougher to do and you can't reasonably determine it for every car in every location under every possible circumstance. There are trains built and run that will just plain derail if the go into emergency at the right spot. But, they don't, so no news is good news...
How long did it take from the beginning of the railroad era for engineers to work out the mathematics to explain all the forces impacting trains operations? Or is it still a work in progress?
JPS1 oltmannd Which even my "back of the envelope" calculation showed is what likely happened. Getting to L/V is tougher to do and you can't reasonably determine it for every car in every location under every possible circumstance. There are trains built and run that will just plain derail if the go into emergency at the right spot. But, they don't, so no news is good news... How long did it take from the beginning of the railroad era for engineers to work out the mathematics to explain all the forces impacting operations? Or is it still a work in progress?
How long did it take from the beginning of the railroad era for engineers to work out the mathematics to explain all the forces impacting operations? Or is it still a work in progress?
Still a work in progress as they try to maximize tonnage and minimize costs.
BaltACD JPS1 oltmannd Which even my "back of the envelope" calculation showed is what likely happened. Getting to L/V is tougher to do and you can't reasonably determine it for every car in every location under every possible circumstance. There are trains built and run that will just plain derail if the go into emergency at the right spot. But, they don't, so no news is good news... How long did it take from the beginning of the railroad era for engineers to work out the mathematics to explain all the forces impacting operations? Or is it still a work in progress? Still a work in progress as they try to maximize tonnage and minimize costs.
I would think they would have a program that would predict the stringline potential of any given train, based on makeup, gradient, power, and curvature. Maybe it could also take over and prevent the stringline event from happening.
Writing such a program is not that difficult. If the train is approching the stringline point information could be bass to the PTC system which could then slow the train down.
Caldreamer
caldreamerWriting such a program is not that difficult. If the train is approching the stringline point information could be bass to the PTC system which could then slow the train down.
Stringlining can come from approaching a curve too slow, necessitating you to go deeper into the throttle quicker to keep from stalling. More about yanking it too hard, than going too fast.
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
caldreamer Writing such a program is not that difficult. If the train is approching the stringline point information could be bass to the PTC system which could then slow the train down. Caldreamer
It's not the speed, really. It's the force the locomotives are generating. The train just "pulls back" with train resistence plus acceleration.
JPS1 oltmannd Which even my "back of the envelope" calculation showed is what likely happened. Getting to L/V is tougher to do and you can't reasonably determine it for every car in every location under every possible circumstance. There are trains built and run that will just plain derail if the go into emergency at the right spot. But, they don't, so no news is good news... How long did it take from the beginning of the railroad era for engineers to work out the mathematics to explain all the forces impacting trains operations? Or is it still a work in progress?
There are, and have been for quite a while, simulations that will calculate L/V for a train dynamically. They have typically been used to help find derailment causes and figure out what general rules, if any, could be used to reasonably avoid the situation in the future.
The derailment several months ago on the CSX's Baltimore Belt Line that overturned cars into and damaging parts of the Baltimore Streetcar Museum was a stingline event caused with the DPU lost communications with the head end locomotives and shut down thus creating excessive trailing tonnage for the curvature the head end was operating through.
Excessive trailing tonnage can happen, even when you aren't expecting it.
Euclid BaltACD JPS1 oltmannd Which even my "back of the envelope" calculation showed is what likely happened. Getting to L/V is tougher to do and you can't reasonably determine it for every car in every location under every possible circumstance. There are trains built and run that will just plain derail if the go into emergency at the right spot. But, they don't, so no news is good news... How long did it take from the beginning of the railroad era for engineers to work out the mathematics to explain all the forces impacting operations? Or is it still a work in progress? Still a work in progress as they try to maximize tonnage and minimize costs. I would think they would have a program that would predict the stringline potential of any given train, based on makeup, gradient, power, and curvature. Maybe it could also take over and prevent the stringline event from happening.
I am referring to a program that would prevent stringlining by knowing the train makeup and tonnage distrubution, and knowing the train's location on the railroad line, while monitoring tractive effort. By knowing the train makeup and tonnage distribution, it would know where the stringline threshold is at every point on the line. It would have a built-in safety margin, and would reduce tractive effort if the stringline threshold was getting too close.
With this magic system, you would not have the problem of a difference of opinion as to whether or not a train would stringline.
EuclidI am referring to a program that would prevent stringlining by knowing the train makeup and tonnage distrubution, and knowing the train's location on the railroad line, while monitoring tractive effort. By knowing the train makeup and tonnage distribution, it would know where the stringline threshold is at every point on the line. It would have a built-in safety margin, and would reduce tractive effort if the stringline threshold was getting too close. With this magic system, you would not have the problem of a difference of opinion as to whether or not a train would stringline.
They've had that stuff since LEADER.
zugmann Euclid I am referring to a program that would prevent stringlining by knowing the train makeup and tonnage distrubution, and knowing the train's location on the railroad line, while monitoring tractive effort. By knowing the train makeup and tonnage distribution, it would know where the stringline threshold is at every point on the line. It would have a built-in safety margin, and would reduce tractive effort if the stringline threshold was getting too close. With this magic system, you would not have the problem of a difference of opinion as to whether or not a train would stringline. They've had that stuff since LEADER.
Euclid I am referring to a program that would prevent stringlining by knowing the train makeup and tonnage distrubution, and knowing the train's location on the railroad line, while monitoring tractive effort. By knowing the train makeup and tonnage distribution, it would know where the stringline threshold is at every point on the line. It would have a built-in safety margin, and would reduce tractive effort if the stringline threshold was getting too close. With this magic system, you would not have the problem of a difference of opinion as to whether or not a train would stringline.
Then why are they stringlining trains?
EuclidThen why are they stringlining trains?
I don't know. Why are they?
Euclid zugmann Euclid I am referring to a program that would prevent stringlining by knowing the train makeup and tonnage distrubution, and knowing the train's location on the railroad line, while monitoring tractive effort. By knowing the train makeup and tonnage distribution, it would know where the stringline threshold is at every point on the line. It would have a built-in safety margin, and would reduce tractive effort if the stringline threshold was getting too close. With this magic system, you would not have the problem of a difference of opinion as to whether or not a train would stringline. They've had that stuff since LEADER. Then why are they stringlining trains?
Sometimes reality intrudes into fairyland.
see title of post!
So, short story about testing SD60MACs on Conrail.
Our department was coordinating the test - me in particular. So, they wanted to run an ore train of solid ore jennies west over HSC. "We want to put all three SD60MACs on line and see if we can't pull the hill without helpers." said the division. "No. It won't work. You'll get a knuckle. You need to push the train." we said. "We just want to try it." Said the division. "Don't." we said.
They tried it. Didn't even get to the brickyard. Bang! Pulled the entire draftgear out of one of those old 100 ton ore jennies.
"We told you so." we thought to ourselves.
They guys who are pretty astute about budgets, rules and safety aren't always the best at physics....
Thirty-three train cars derailed yesterday morning roughly 30 miles from the Nevada-Utah border near the small town of Caliente
https://www.msn.com/en-us/autos/news/brand-new-jeep-gladiators-and-chevy-silverados-destroyed-after-train-derails-in-nevada/ar-AAEbqlI?ocid=spartanntp
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