JMP -
I'm not able to see the images you posted. I was down there late this afternoon today. Really lucky none of the homes in Glencoe were hit. What a sight seeing all the cars mangled about and coal everywhere!
I would also like to give a very big THANK YOU to the RJ Corman employee who helped me out when I got stuck in Glencoe as well to a man and his wife who helped me when I got stuck (again) on the way out of Glencoe.
Red X's for the masses.
Never too old to have a happy childhood!
Thanks for the responces. I also found (somewhere) that DB provides a range of 50%-70% of braking, according to EMD.
Ed
MP173Paul:Thanks for the info. <snipped>3. Are locomotives other than gensets, using the energy generated by DB? Obviously the energy is disapated thru heat, which tends to indicate no energy is stored or used....but is it all disapated (wasted)? ed
Paul:Thanks for the info.
3. Are locomotives other than gensets, using the energy generated by DB? Obviously the energy is disapated thru heat, which tends to indicate no energy is stored or used....but is it all disapated (wasted)?
ed
Modern electric locomotives such as NJ Transit's ALP46 locomotives and Amtrak's HHP-8 can feed it back into the Cantenary where other trains can make use of it.
1. Why the 10 second delay before beginning the use of dynamic brakes? Is that simply a conversion time to go from traction motor to generator? (hope the correct terms were used)
Right, if the transition from power to db is to fast, the various circuits/components could be damaged.
2. Why the restriction of amps thru turnouts?
Draft forces could cause a derailment. Think about the force at the very front axle of a train when in db controlling 15,000+ tons. Usually these types of restrictions come into play within slow orders, turnouts, sharp corners, yard tracks or when pushing (shoving) trains.
No. The generators disapate their energy via heat through what I call toasters )Well very big and powerfull toasters). The energy created is not used at this time.
Good questions, Ed, - the balance or combination or 'trade-off' between air and dynamic brakes - 'cause I don't know of any quick and easy answers. In theory, the necessary braking effort on many grades could be adequately supplied by either all dynamics, all air brakes, or many combinations of the two. But in practice, my general understanding is as follows - and subject to correction and supplementation by the 'working rails' here:
Some of the answers will specifically depend on - and vary greatly with - the number and type of units, number of powered axles, dynamic braking features and capability, and the number of cars / 'Operable Brakes' and 'TPOB' = 'Tons Per Operable Brake'. That said -
It seems there is a preference to avoid using the air - and hence to primarily rely on the dynamic brakes - as much as possible. There seem to be a couple reason for that - better slack control, faster 'releases', less risk of triggering an undersired emergency application or 'dynamiter' with a faulty or too-sensitive triple valve, etc. The dynamic brakes can reliably slow a train down to around 12 to 16 MPH, and sometimes slower if they are 'extended range' - after/ below which the air is needed to achieve a complete stop. But to hold a train at a dead stop on a grade requires the air - the dynamics are effective only when the lcomotives are moving, and that's not what's wanted in that particular situation.
Yes, both air and dynamics would likely be needed for the 2.0 % grade.
But for the 0.5 % grade, likely the dynamics alone would be enough.
Here are some excerpts from the NS ETT and Rules applicable to the Horseshoe Curve area. To help you understand this better, please know that Cresson is a little further west from UN/ AR, which is just beyond the top of the grade; Benny is near the top; and MP PT 238.0 is near or at SLOPE at the bottom, just outside of Altoona You'll also see that Rule L-210. Dynamic Brake, subsections (c), (d), and (e), address some questoins that you had earlier about checking and assuring that the dynamics are fully operable, or not:
http://blet73.org/Pittsburgh_Division_Timetable.pdf
PITTSBURGH LINE - 9. DISTRICT INSTRUCTIONS
A. SUPPLEMENTARY INSTRUCTIONS IN HANDLING EASTWARD TRAINS FROM CRESSON TO ALTOONA
Rear-end dynamic braking will be used when available.
If the brake pipe pressure on the controlling engine drops to 70 lbs. for any reason, the train must be stopped and secured. Train must not proceed until brake pipe pressure has been restored.
Eastward freight trains on Pittsburgh Line between UN/AR and MP PT 238.0, stopping for any reason, will properly secure train with hand brakes, prior to releasing automatic air brake.
All eastward freight trains, except those consisting exclusively of solid loaded bulk commodity cars, when operating between Benny and Slope, must not exceed 6th throttle position in dynamic braking on head end of train.
Running releases of the automatic train brakes are prohibited on eastward freight trains between UN/AR and MP PT 238.0, except when retainers are set in high pressure position.
3. Between UN/AR and Slope, maximum tonnage per axle of dynamic brake is 800 tons.
If the tonnage of the train is greater than the dynamic braking force of the units involved (hauler and helper), less than 4 axles of dynamic braking on hauler, or the dynamic brake or pressure-maintaining feature, or both, fail, instructions governing trains with non-equipped engines will govern.
If the tonnage exceeds 800 tons per axle dynamic braking, one (1) retaining valve must be used for each 100 tons in excess thereof, or Conductor and Engineer will be governed by instructions of Division Superintendent.
When retaining valves are required, a minimum of no less than 10 retaining valves will be set beginning from head end, in high pressure position on loaded cars and in low pressure position on empty cars.
4. Average tons per operative brake must not exceed 140 tons.
Retaining valves will be placed in high pressure position on 50% of cars in train beginning from head end.
From the NS-1 - RULES FOR EQUIPMENT OPERATION AND HANDLING - EFFECTIVE: OCTOBER 1, 2007, pages 52 - 54 [60 - 62 of 143 of the 'PDF' version] at - - http://blet73.org/NS-1_Rules.pdf
L-210. DYNAMIC BRAKE
(a) Use of Dynamic Brake
The dynamic brake amperage must be increased gradually, allowing slack to bunch safely against the locomotive.
The dynamic brake must not be released in severe undulating (rip-rap) terrain or on a heavy descending grade. It can be released with train on level grade or at bottom of grade with the locomotive on ascending grade. When releasing dynamic brake, time must be allowed for slack to adjust before applying power.
If necessary, automatic air brake may be used with dynamic brake applied. After each air brake application, the independent brake handle must be depressed frequently and held at least 4 seconds for each unit in the consist and until brake pipe exhaust ceases, in order to keep locomotive brakes released. When making a running release of train air brakes, the dynamic brake must be kept fully applied with maximum amperage until air brakes have released throughout the train.
1.
When making a planned stop with other than solid loaded bulk commodity trains and using more than the equivalent of 14-axles of EXTENDED RANGE dynamic brake (as referenced in the NS Locomotive series table), the dynamic brake must be reduced to 400 AMPS or less (40,000 lbs. braking effort or less on “AC” units) when applying the train air brake.
2.
EXCEPTIONS:
(2) The equivalent of 24-axles of dynamic braking may be used for designated trains handling only loaded 100 ton cars equipped with high tensile (Grade E) knuckles and couplers.
If the locomotive consist is made up of
• review the completed Form ME-112 that has been left in the cab of the controlling locomotive
• leave the form in the cab of the controlling locomotive in the consist
• discard any previously completed forms
• locomotive initial and number
• name of the discovering railroad
• location and date where the condition was discovered
• signature of the person discovering the condition
• controlling the dynamic brake effort in the trailing locomotives in the consist that are so equipped
• displaying to the locomotive Engineer the deceleration rate of the train or the total train dynamic brake retarding force
- Paul North.
MP173 Balt:Perhaps what I am attempting to visualize is what role do dynamic brakes apply in train handling? Is it best not to use air if possible???using the dynamics to stay away from air brake applications? Perhaps better, is there a Dynamic Braking for Dummies section out there for me to read? Fascinating stuff. Ed
Balt:Perhaps what I am attempting to visualize is what role do dynamic brakes apply in train handling? Is it best not to use air if possible???using the dynamics to stay away from air brake applications?
Perhaps better, is there a Dynamic Braking for Dummies section out there for me to read?
Fascinating stuff.
When it comes to handling trains on grades both the air brakes and dynamic brakes are used. On my carrier, if a train does not have enough engines to have sufficient Dynamic Braking Power for the train to descend the grades, it will wait at the summit until Helper engines and crew can get in position to Help the train DOWN the grade. In today's railroading Helpers don't only help trains up grades but also DOWN grades.
Balt:Thanks for the explanation. I sort of understand how dynamic brakes work...dont ask for a two page single spaced report, but the concept is in my mind.
Let's say a heavy train is heading down a mountain grade. Ok, assume it is a 15000 ton coal train. Is it safe to assume that the engineer will need both dynamic brakes and air brakes for controlling the speed on a 2% grade? I think so, but again...I am a non railroading Hoosier.
Lets say you have a .5% grade. Will dynamic brakes hold the train in check? What I am trying to sort out is how much each type of braking system applies to train movement. Ok, I realize each train and each engineer is different and will have their own system or method and more than likely change that based on how the train is handling.
Perhaps what I am attempting to visualize is what role do dynamic brakes apply in train handling? Is it best not to use air if possible???using the dynamics to stay away from air brake applications?
You might find this report on a runaway on CPR back in the late 1990s of interest. The crews were very familiar with SD40-2s, but the new AC4400s were a major technological leap. Not all the differences were fully appreciated. In the SD40s, when the lever was set for dynamic brake, the dynamic brake would work. Not necessarily so with the AC4400s..... They had come to a stop with an emergency brake application, which had automatically cancelled the DB. Unknown to the crew, the microprocessor required to be reset by moving the throttle out of the DB position before the DB would be restored into operation. Shortcutting the operating rules, but expecting the DB would control the train as usual while the brake line was recharged, they released the brakes. The microprocessor refused to allow the DB to operate, the air was not enough to hold the train, and they had a wild ride down the Field Hill. The units stayed on the track, but all the train except the front drawbar was scattered around various curves. That particular gap in training was instantly widely known!
John
http://www.tsb.gc.ca/eng/rapports-reports/rail/1997/r97c0147/r97c0147.asp
Sorry - you might have to cut and paste to get this link to work properly - I haven't figured out the correct method.
.....And that east 12 mile grade of up to 1.8% {in general}, contains plenty of curves including Horseshoe that rate severe attention.
Quentin
I am not an engineer, but have had a lot of time riding the head end and questioning Engineers about their craft.
Operating trains, especially in difficult terrain, is a very 'formulaic' operation with a number of 'measuring marks' as the train progresses along the terrain. ie.
20 car lengths past the crest initiate a 10 pound brake pipe reduction and go from power to dynamic braking.
50 car lengths past the crest speed should be 15 MPH and 600 amps reading on dynamics
entire train over crest speed 15 MPH and 900 amps on dynamics
MP 3 from crest a flat section can let speed increase to 20 MPH releasing dynamics.
MP 5 from crest begins another decent, activate dynamics again to reduce speed to 12 MPH and let dynamics build to 1000 amps and train will maintain 15 MPH to MP 7.
So on an so forth as the train progresses....this knowledge is part of what it means for a Engineer to be qualified on a particular territory and it is not knowledge that gets taught from a book....Variations from the expected conditions at any point are the things that generate alarm to the Engineer that the train may have some problems....the train may be going too slow or too fast, the normal brake pipe reduction may not have the expected effect on train speed, dynamic brake application may not have the expected retardation, the use of power to drag the train through a sag may not be able to maintain the expected speed with the brakes applied through the train....those and 1001 other things that speak to the engineer on his abilities to handle THIS PARTICULAR train. Each train is it's own adventure.
I'm not a locomotive engineer either, so I'll gladly defer to those who are, to answer those portions of your questions. EDIT - Also, I have no detailed knowledge of CSX's operations over those grades, so again I'll defer to those that do, or have access to such information.
In the meantime, the portions of the NS and CR timetables that I referenced and linked to over on this concurrent thread - Break [sic] checks @ Gallitzin, PA, at - http://cs.trains.com/trccs/forums/t/168584.aspx - may answer some of your questions. That's only about 12 miles of 1.4 to 1.8 percent grades, with the first mile at 2.36 percent - but it's still a potentially dangerous mountain grade. But it seems to be a lot like how porcupines make love - ''Very carefully''. The January 1985 Trains article by Fred Frailey that I also referenced has about a page's worth of text on it - though spread over several pages, so it's hard to summarize. Basically, it's stop, check the brakes, and proceed slowly. If there is any doubt at all - 'Safety is of the first importance'. The Superintendent then had rules and apparently enough supervisory staff to help the trainmen check out questionable situations - I recall a quote something like, ''If a train has trouble on that mountain, I want someone there to help it - even if it's the ConRail police.'' Frailey also described a train that had an undesired emergency brake application - the Road Foreman of Engines and a Trainmaster supervised a lengthy brake test at the Gallitzin summit before the train was allowed to proceed. It doesn't hurt at all that there are like 6 to 8 helper sets on duty on that mountain based at Cresson at most times, so they can be added to the front or rear almost 'as needed' or wanted. The proof , though, is in the experience/ history - no runaways that have led to derailments in recent history there (''Praise be to God and Allah'', ''Knock on wood'', etc.)
Paul:Thanks for the link for the STB report on the derailment. I read the entire document. What a horrible feeling that must be for the crew to realize you have no control.
Please understand that a) I am not a railroader and b) and live in Indiana where we have very few grades.
Is it now mandatory or common practice that the engineer will have real time indications of the functions of the dynamic braking system or all units? That seems to be the root of the problem in the earlier accident (unless I am misreading/misunderstanding).
What determines an engineer's train handling plan when accepting such a coal train on a mountain grade. Are there rules of thumb, regarding dynamic brake/airbrake use? I understand the maximum speed is listed by timetable (revised after the accident) and there are maximum allowable amounts of air reduction, but how does an engineer safely move 15,000tons of lading down 17 miles of 2.0 percent grade or more? Will an experienced engineer understand the tonnage/horsepower (perhaps braking capacity) and have a plan? How much does weather play into the movement?
Does an engineer have mental guidelines (such as at MP173 I need to have the train at ____ speed)?
Mountain railroading and mountain driving of tractor trailers require a special mindset and respect.
Like GP40-2 said, we have about 3 feet of snow here in Somerset and surrouding area. Temp on Saturday was low teens. At the time of the derailmen the snow would've been coming down at a good clip and, most likely, would've been closer to 2 feet on the ground.
Murphy Siding Did that area see heavy snowfall recently, like Washington D.C. (and all the rest of us) ?
Did that area see heavy snowfall recently, like Washington D.C. (and all the rest of us) ?
In the Sand Patch incident both engines were GE AC's....one Heavy and one 'regular'.
]
Paul:
1. You mentioned only two units on front. Do you know their eng #s and if they were ACs or DCs?
2. you made me think that maybe this current wreck they were in either partial or full dynamics and maybe one, or more than one traction motors began having progresively occuring ground faults due to snow ingestion?
The engineer applies additional brake pipe reductions but before they take effect the train suddenly picks up speed and exceeds the critical speed?
With all the reported snow ground faults are definitely a possibility. The heavy snow on possibily 132 tons per operative brake. Take a posible brake problem this wreck may be a combination failure any one item might not have caused the accident but putting all together --------?
quote user="Paul_D_North_Jr"]Unfortunately, problems can occur when, as in this accident, the dynamic braking system functions only partially or suddenly and unexpectedly fails when the train is moving too fast to be stopped by the air brakes alone[/quote][quote user="Paul_D_North_Jr"]
Paul_D_North_Jr The January 30, 2000 runaway derailment of a CSX coal train on the same grade appears to be superficially similar - except that train was only 80 cars instead of the 131 or 64 % more here - and had 3 locomotives, albeit without dynamic brakes on 2 of them, as against only 2 here. Here's the link to the NTSB's report on that event: http://www.ntsb.gov/publictn/2002/RAR0202.pdf Title: Railroad Accident Report: Derailment of CSX Transportation Coal Train V986-26 at Bloomington, Maryland, January 30, 2000 NTSB Report Number: RAR-02-02, adopted on 2/5/2002 [Summary | PDF Document] NTIS Report Number: PB2002-916302 From the top of page 13: ''The first unit, CSXT 806, was an SD80MAC; BNSF 9481 was an SD70MAC; and CSXT 8666 was an SD50. On these units, maximum dynamic braking is achieved when the locomotive is traveling between 4 and 24 mph. The maximum dynamic braking effort is 96,000 pounds for an SD80MAC, 81,000 pounds for an SD70MAC, and 60,000 pounds for an SD50. The accident train had 80 coal cars, all of which were high-side 'bathtub' gondola cars designed for unit coal train service. [snip] According to the CSXT consist list, the train was 4,145 feet long (the length of the combined cars was 3,920 feet). The trailing tonnage (the cars only) was 10,569 tons, and the tons per operative brake [FN 27] was 132. [FN 27] Tons per operative brake is the total trailing tonnage divided by the number of freight car brake control valves, which usually corresponds to one per car, as in this case.'' From page 27 of the report [emphasis added - PDN]: ''Dynamic braking on the two trailing locomotive units, while available, could not be activated because of the defective multiple-unit cable between the first and second locomotive units. Because he did not have the benefit of full dynamic braking, the engineer had to increase the air brake application beyond what normally would have been expected in order to control speed. By so doing, he unwittingly overheated the tread-brake system. Further, the maximum authorized speed for the accident grade had been established based on the assumed availability and use of dynamic braking. Judging from the CSXT.s experience of successfully negotiating 17-mile grade at the maximum authorized speed, the combination of dynamic and air braking was, in fact, adequate to hold a train at or under the established maximum authorized speed as the train progressed down the grade. The Safety Board concludes that if all the available dynamic braking could have been activated on the accident train, the derailment probably would not have occurred. Unfortunately, problems can occur when, as in this accident, the dynamic braking system functions only partially or suddenly and unexpectedly fails when the train is moving too fast to be stopped by the air brakes alone. Calculations and dynamometer testing confirmed that CSXT eastbound loaded coal trains on 17-mile grade could not be controlled or stopped at the maximum authorized speed without the use of significant dynamic braking. The Safety Board concludes that by using the effects of dynamic braking in its speed calculations, CSXT established a maximum authorized speed over and down 17-mile grade that was too high to ensure that heavily loaded trains could be stopped using air brakes alone.'' It will be most interesting to see what the investigation of this accident reveals. - Paul North.
The January 30, 2000 runaway derailment of a CSX coal train on the same grade appears to be superficially similar - except that train was only 80 cars instead of the 131 or 64 % more here - and had 3 locomotives, albeit without dynamic brakes on 2 of them, as against only 2 here. Here's the link to the NTSB's report on that event:
http://www.ntsb.gov/publictn/2002/RAR0202.pdf
Title: Railroad Accident Report: Derailment of CSX Transportation Coal Train V986-26 at Bloomington, Maryland, January 30, 2000
NTSB Report Number: RAR-02-02, adopted on 2/5/2002 [Summary | PDF Document]
NTIS Report Number: PB2002-916302
From the top of page 13:
''The first unit, CSXT 806, was an SD80MAC; BNSF 9481 was an SD70MAC; and CSXT 8666 was an SD50. On these units, maximum dynamic braking is achieved when the locomotive is traveling between 4 and 24 mph. The maximum dynamic braking effort is 96,000 pounds for an SD80MAC, 81,000 pounds for an SD70MAC, and 60,000 pounds for an SD50.
The accident train had 80 coal cars, all of which were high-side 'bathtub' gondola cars designed for unit coal train service. [snip]
According to the CSXT consist list, the train was 4,145 feet long (the length of the combined cars was 3,920 feet). The trailing tonnage (the cars only) was 10,569 tons, and the tons per operative brake [FN 27] was 132.
[FN 27]
From page 27 of the report [emphasis added - PDN]:
''Dynamic braking on the two trailing locomotive units, while available, could not be activated because of the defective multiple-unit cable between the first and second locomotive units. Because he did not have the benefit of full dynamic braking, the engineer had to increase the air brake application beyond what normally would have been expected in order to control speed. By so doing, he unwittingly overheated the tread-brake system. Further, the maximum authorized speed for the accident grade had been established based on the assumed availability and use of dynamic braking. Judging from the CSXT.s experience of successfully negotiating 17-mile grade at the maximum authorized speed, the combination of dynamic and air braking was, in fact, adequate to hold a train at or under the established maximum authorized speed as the train progressed down the grade. The Safety Board concludes that if all the available dynamic braking could have been activated on the accident train, the derailment probably would not have occurred.
Unfortunately, problems can occur when, as in this accident, the dynamic braking system functions only partially or suddenly and unexpectedly fails when the train is moving too fast to be stopped by the air brakes alone. Calculations and dynamometer testing confirmed that CSXT eastbound loaded coal trains on 17-mile grade could not be controlled or stopped at the maximum authorized speed without the use of significant dynamic braking. The Safety Board concludes that by using the effects of dynamic braking in its speed calculations, CSXT established a maximum authorized speed over and down 17-mile grade that was too high to ensure that heavily loaded trains could be stopped using air brakes alone.''
It will be most interesting to see what the investigation of this accident reveals.
jeffhergertKnowing about as much as anyone else does at this point (nothing really), I hate to go out on a limb. I couldn't live with myself if I knew that I caused brother Wabash to pull a muscle while rolling around like that. So here goes. Does anyone know what the temperature was? I'm thinking less along the lines of ice in the train line. More that maybe the temp caused the air hose gaskets to leak. I don't know how they operate down the hill, but if they release the air they may not get a good recharge of the train line before the next set. If they had stopped to cut off helpers, they may not have had a good charge in the train line to begin with. In effect they piddled (PC version) away their air. Will just have to wait and see. Jeff
Knowing about as much as anyone else does at this point (nothing really), I hate to go out on a limb. I couldn't live with myself if I knew that I caused brother Wabash to pull a muscle while rolling around like that. So here goes.
Does anyone know what the temperature was? I'm thinking less along the lines of ice in the train line. More that maybe the temp caused the air hose gaskets to leak. I don't know how they operate down the hill, but if they release the air they may not get a good recharge of the train line before the next set. If they had stopped to cut off helpers, they may not have had a good charge in the train line to begin with. In effect they piddled (PC version) away their air.
Will just have to wait and see.
Jeff
Ten years and one week ago to the day, on the nearby Seventeen-mile grade they had a fatal runaway accident. In that case the Engineer let the speed build up a little too high (on the order of 5 mph IIRC) and the trains brakes burned out. An emergency application just speeded up the process. Mountain grades are very unforgiving. I think it unlikely that he wasted his air, since they are carefully warned about that little trap, but anything is possible. Do all locomotives now have the Dynamic Brake Hold feature on an Emergency Brake application?
Y.E.onDOMReady(show_notes_initially); ROFLAC? Is that the same thing as AFLAC? wabash1: Do I sense that you pehaps disagree with something written above?
Thanks to Chris / CopCarSS for my avatar.
ROFLAC
Ice in the line even if the EOT was told to set the brakes FORGET IT will not happen. See the ice acts like someone turn the anglecock between the cars and your done. Now imagine that you have that in 4-5 spots your talking about no way in HELL would they have been able to stop or contrl this monster.
CShaveRRI haven't seen photographs of the actual wreck yet. That's another suggestion that the weather's none too good up there.
Carl......I just sent you a Somerset DailyAmerican page of said CSX wreck. You can certainly tell from the included photo, there was plenty of snow....I'd say up to 2' or more....100 plus cars included in the wreck will be major.....
Carl
Railroader Emeritus (practiced railroading for 46 years--and in 2010 I finally got it right!)
CAACSCOCOM--I don't want to behave improperly, so I just won't behave at all. (SM)
I have cash that is saying somewhere in that train was a frozen brake. That and extra weight from all the snow this stuff was basically Donner Cement that was falling. You take 14K tons of train add another 2K of snow and then make the rails slicker than snot with moisture no then only give them 2 units to get down the mountian in freezing temps are you nuts.
CShaveRRSome photographs I saw from Cumberland suggest that they got quite a bit of snow in the area. I suspect that the weather was somehow a contributing factor. I haven't seen photographs of the actual wreck yet. That's another suggestion that the weather's none too good up there. Today is at least two days after the wreck--restoration of the line ought to be well on the way, if it isn't already open.
There is a rather poor picture of the derailment accompanying this local news story, but it should give you some idea of the amount of work that Hulcher and R.J. Corman are facing. Reportedly two response teams from each company were summoned because of the size of the derailment and the difficult conditions.
Somerset Daily-American story
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