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 ismoving too fast to be stopped by the air brakes alone
[/quote]
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.
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.
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
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 ap
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!
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?
Perhaps better, is there a Dynamic Braking for Dummies section out there for me to read?
The current practices that are being taught to Engineers, especially where AC engines predominate with their Extended Range Dynamic Braking abilities are for Dynamics to be used in ‘most’ routine braking situation. Air Brake valves on cars can and do, initiate a Emergency Brake Application when the Engineer has only made a routine service application of the brakes…depending on your slang this is called a KICKER, a DYNAMITER and probably a dozen other different monikers. In the era of the 3500/4000 foot train with both head end and rear end crews to perform necessary train inspections…this UDE was not that big of a delay. With today’s 9000 foot and longer trains with HAZMAT and just a head end crew, a UDE can cause very significant delays…3 & 4 hours is not unheard of, so use of air brakes is discouraged unless absolutely necessary for safe operation of the train.
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.
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
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)
Why the restriction of amps thru turnouts?
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)?
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.
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.
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)?
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.
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.
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.
Paul D.North in yur post you made Ive got questions on what you posted.
on your post you say employee time table and then i read alittle further it seems you state that rule L 210 and rule L 240 are timetable rules. is this correct ?
you posted a part of the timetable that says all eastward trains except solid bulk commoditie trains operated from benny and sloop must not exceed notch 6 in dynamic, what if your engines is 3 dash-9s and are flat dynamic?
who gives you the paper work on condition of engines and what if out of 3 engines you only have 1 engine with operational dynamic brakes.
No - not from the ETT. I had a little heading in there that you might have missed. L-210 and L-240 are -
"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 ".
[D)] [Displays-Lack-Of-Knowledge-Dept.] What do you mean by “flat dynamic” ? And what’s the significance of the Dash-9’s ? I recall we had a discussion about this kind of thing back in mid-August 2009 when I observed what appeared to be a rear helper pushing a double-stack EB past Horseshoe Curve, for which I still owe you a better answer, which I don’t have yet.
There’s a ‘turnover form’ for NS - ME-112, I think it is - that is supposed to be there at the start of each shift. If the DB is inoperative, a ME-109 tag is supposed to be filled-out and attached. I was going to post that part eventually - no, I already did = see L-210 (c), (d), and (e), quoted above.
Well, first at least you then know that you have only 1 in working condition. If that’s not up to the task at hand, then it’s time for a ‘Good Faith Challenge’ - which is a whole 'nother topic. Perhaps that’s what this CSX crew should have done ?