I have a basic understanding of how air braking and dynamic braking work on a train. But in discussions I’ve read about retainers, there is mention that dynamic brakes have almost rendered retainers obsolete. Is it actually meant that the combination of normal air braking and dynamics means retainers are not necessary?
Say a heavy 120-car train is descending a 1.5% grade. I assume the dynamics would be hard at work continuously. But what else is going on? Is the engineer doing a service application of the train-line air brakes at regular intervals? My understanding is that RR air brakes are either fully on or fully off. So would our hogger, say, do a 1-minute application every 5 minutes, or something like that? How long does it take to deplete the individual reservoirs on the cars? Then how long does it take to re-pressurize the train-line (and reservoirs)? Even six big units with dynamics would seem to be little match for 120 loaded hoppers pushing from behind on a steep downgrade. Also, without airbrakes, it would seem like the train would try to overrun the locos and jackknife, even if the dynamics were that strong. So what exactly is the routine? I’d love to hear from an experienced engineer. Sorry if my terminology is incorrect.
Still in training.
You are mistaken about airbrakes being fully on or fully off. Both airbrakes znd dyazmic brakes are capable of gradations. And for airbrakes this applies to both the train-line airbrake, which acts to reduce pressure in the train line, with "dumping" or "big-holing" meaning exhausting the train line as rapidly as possible being the emergency application, as well as the independent locomoive brake, which simply feeds pressure to the locomotive's brake cylinders. The right amount of train-line pressure reduction for a partiular situation is one of the important skills of a good engineers. With dynamics, the right comibnation is important. There are times when cycling airbrakes between off and some pressure reduction may be useful, but I will an explaition of why and when to others running trains regularly.
LithoniaOperatorMy understanding is that RR air brakes are either fully on or fully off.
Not so. The train brakes can be applied in increasing increments. A "first service" is about a six pound reduction of the pressure in the brake pipe. "Full service" is the point where you're braking as much as possible, that's about a 26 pound reduction. Once you've made a first service, you can continue to reduce the pressure in the brake pipe (ie, step harder on the brakes) until you reach full service.
It's the release that's all or nothing, at least on freight trains (passenger has a feature called "graduated release). So you can't just let off on the brakes a little bit if you find you've taken too much - you have to fully release the brakes, which must then recharge.
In come cases, a first service application may do a nice job of holding the train on a downgrade. If it does, you're all set. If it doesn't, you can add a little more if needed, or you have to release the brakes entirely. Sometimes you'll use a little power down the hill if that first service is a bit too much.
If you are using retainers, some of the pressure in the brake cylinders on the cars will be "retained," effectively leaving a set on the cars. Meantime, the engineer can release the brakes and recharge the system.
If dynamics can't hold the train (and I've slipped the dynamics on wet/leafy/icy rail), then air will be necessary.
Cycle braking can be what gets a train in trouble, if there is insufficient time allowed to recharge the reservoirs on the cars. Each application provides a little less braking force, until finally there is none at all. A good many runaways have been attributed to exactly this phenomenon.
Time to recharge will vary, but will definitely be much longer for longer trains, in cold weather, etc. On my short trains, it's measured in seconds, but a long train might take a few minutes, especially from a deep application.
If you haven't already read Al Krug's excellent primer on railroad air brakes, you'll find it well worth your while. http://www.railway-technical.com/trains/rolling-stock-index-l/train-equipment/brakes/north-american-freight.html
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...
Tree, thanks so much for your excellent explanation. I really appreciate your taking the time to write all that.
There is one sentence I don't get though:"Sometimes you'll use a little power down the hill if that first service is a bit too much." Do you mean turn off the dynamics and have the engine(s) pull against the train's brakes somewhat? If so, is that bad for the brake shoes/wheels if done too long?
Oh, and by "cycle braking" do you mean on/off/on/off as I had described?
I will definitely read the linked article.
Thanks again!
LithoniaOperatorThere is one sentence I don't get though:"Sometimes you'll use a little power down the hill if that first service is a bit too much." Do you mean turn off the dynamics and have the engine(s) pull against the train's brakes somewhat?
LithoniaOperatorIf so, is that bad for the brake shoes/wheels if done too long?
tree68Cycle braking can be what gets a train in trouble, if there is insufficient time allowed to recharge the reservoirs on the cars. Each application provides a little less braking force, until finally there is none at all. A good many runaways have been attributed to exactly this phenomenon.
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BigJim LithoniaOperator There is one sentence I don't get though:"Sometimes you'll use a little power down the hill if that first service is a bit too much." Do you mean turn off the dynamics and have the engine(s) pull against the train's brakes somewhat? Yes. The object of taking a train down the hill is to BALANCE the force of gravity against the retarding forces of dynamic braking and/or the air brakes. This fine when the grade is constant. Sometimes the grade happens to be slight enough that it can be controlled with modulating the power of the dynamic brake. Then, there are times that the grade is steep enough that the dynamic brake can no longer hold back the train. [Keep in mind that RR's limit the amount of [equivilent]axles that can be used in dynamic braking so that the buff forces do not jack-knife the train.] In that case air must be used to help retard the train. The least amount of air, the better. This is all well and good until in the middle of this steeper grade you have to traverse a lesser grade that just happens to be so short that you don't have time enough to knock of the train [automatic] brake and have it fully charge before you start down the steeper grade again and have to reapply the automatic. In this case, I have often left the air applied and eased off the dynamic brake and pulled the train through the flatter section until the dynamic was needed again. LithoniaOperator If so, is that bad for the brake shoes/wheels if done too long? On normal grades, this would not be a factor. However, there are grades in places around the country that are very steep. So much so that speed down the hill is limited by timetable rules so that the brakes shoes do not get so hot that they lose their effectiveness. This has been the cause of a number of derailments where the train has run away because the speed was allowed to get over the point of braking effectiveness. tree68 Cycle braking can be what gets a train in trouble, if there is insufficient time allowed to recharge the reservoirs on the cars. Each application provides a little less braking force, until finally there is none at all. A good many runaways have been attributed to exactly this phenomenon. Let me say this about that:tree68 is correct, but, there is a bit "relativity" that needs to addressed. When you first apply the automatic brake from a FULLY charged trainline, let's say a ten pound reduction, there is a certain, "comfortable", feel to the train when the brakes set up. Each time you make this reduction from a fully charged trainline, you get that same feeling from the train.Now, if you release the brake and have to very shortly make another application, you don't get the same feeling from that ten pound reduction. Why? Because the braking system isn't fully charged, and, because it isn't fully charged, the brake control valve doesn't apply as much pressure as it would have if it had been fully charged. So, you have to make a little further reduction in order to get back to that "happy" place you were in to begin with where the contol valve applied the same amount of pressure as before. This happens every time you "fan" the brake, until you get to the point where you have what we called "pissed all of your air away"!
LithoniaOperator There is one sentence I don't get though:"Sometimes you'll use a little power down the hill if that first service is a bit too much." Do you mean turn off the dynamics and have the engine(s) pull against the train's brakes somewhat?
Yes. The object of taking a train down the hill is to BALANCE the force of gravity against the retarding forces of dynamic braking and/or the air brakes. This fine when the grade is constant. Sometimes the grade happens to be slight enough that it can be controlled with modulating the power of the dynamic brake. Then, there are times that the grade is steep enough that the dynamic brake can no longer hold back the train. [Keep in mind that RR's limit the amount of [equivilent]axles that can be used in dynamic braking so that the buff forces do not jack-knife the train.] In that case air must be used to help retard the train. The least amount of air, the better. This is all well and good until in the middle of this steeper grade you have to traverse a lesser grade that just happens to be so short that you don't have time enough to knock of the train [automatic] brake and have it fully charge before you start down the steeper grade again and have to reapply the automatic. In this case, I have often left the air applied and eased off the dynamic brake and pulled the train through the flatter section until the dynamic was needed again.
LithoniaOperator If so, is that bad for the brake shoes/wheels if done too long?
On normal grades, this would not be a factor. However, there are grades in places around the country that are very steep. So much so that speed down the hill is limited by timetable rules so that the brakes shoes do not get so hot that they lose their effectiveness. This has been the cause of a number of derailments where the train has run away because the speed was allowed to get over the point of braking effectiveness.
tree68 Cycle braking can be what gets a train in trouble, if there is insufficient time allowed to recharge the reservoirs on the cars. Each application provides a little less braking force, until finally there is none at all. A good many runaways have been attributed to exactly this phenomenon.
Let me say this about that:tree68 is correct, but, there is a bit "relativity" that needs to addressed. When you first apply the automatic brake from a FULLY charged trainline, let's say a ten pound reduction, there is a certain, "comfortable", feel to the train when the brakes set up. Each time you make this reduction from a fully charged trainline, you get that same feeling from the train.Now, if you release the brake and have to very shortly make another application, you don't get the same feeling from that ten pound reduction. Why? Because the braking system isn't fully charged, and, because it isn't fully charged, the brake control valve doesn't apply as much pressure as it would have if it had been fully charged. So, you have to make a little further reduction in order to get back to that "happy" place you were in to begin with where the contol valve applied the same amount of pressure as before. This happens every time you "fan" the brake, until you get to the point where you have what we called "pissed all of your air away"!
That was all very interesting and helpful, BigJim. Thanks so much. I think I get the picture now.
I've read articles about the big CSX Sand Patch derailment. Some say the engineer did not brake frequently enough to keep snow/ice from building up between the shoes and the wheels. Others say he cycled the brakes too much and, and, as you say, pisssed away his air. Maybe this is simply a difference of opinion which endures. ??
In any event, being shoved down that grade by 100+ loaded coal hoppers, at speeds reaching the posted limit plus 40 mph, must have been truly terrifying.
BTW, where are retarder levers located? I would assume they are on the bottom of cars, at the reservoirs. But I have read accounts of brakemen setting them from the overhead catwalks, in the old days; so that doesn't jive. How could one have done this from above?
LithoniaOperatorBTW, where are retarder levers located? I would assume they are on the bottom of cars, at the reservoirs. But I have read accounts of brakemen setting them from the overhead catwalks, in the old days; so that doesn't jive. How could one have done this from above?
They are now on the bottoms of the cars where they can be reached without going under the cars.
Recall that at one time brake wheels were "up" and there were roofwalks on the cars. As such, it might be possible to set the retainers while the train was still rolling, although I don't know if that was the practice.
All you need is some form of linkage between the roof and the valve.
"Retarders" are specifically found on the downward slope of classification-yard humps, to control the speed of the car so it will 'just' be able to roll through the switches and bowl and couple to the standing cut with minimum impact. Think of them as a pair of very long ground-mounted brakeshoes that bear on the rims rather than tread. If you wondered why some trains had shiny reflective wheelrims ... they recently passed down a hump and the contact area hasn't rusted up yet.
As I recall the 'older' position of retainers was on the side of the car, and I believe older accounts (e.g. in Railroad Magazine) describe finding them there. If the brake equipment is on the end of the car (as it is for many tank and hopper designs), or if there is a concern with lineside obstacles or clearance problems flipping the retainer improperly, then it makes sense to put it on the end, but in doing so you lose the ability to see at a glance, as the train passes, if the retainers are up or not.
We have had several recent threads, mostly on the explicit topic of holding or controlling trains on steep grades, that have involved discussions of retainers. Apparently many relatively new crews are not being trained in the theory and practice of the retainer system, and do not appreciate the benefit of having some of the consist given a lasting 'light set' which I believe does not go away on running release and recharge.
As I understand it, the prohibition against reliance on dynamic for 'required' braking effort is relatively recent; in older accounts it appeared fairly common to depend on dynamics for train control on relatively steep grades well into the era of outgassing composition brakeshoes. I wonder if it is time to reconsider the objective value of setting blocks of retainers even in this era of minimal crews on enormously overlong consists...
I have a couple of questions about retainers. As I first understood them, they retained some pressure on the brakes when they were released. Later, I remember reading something about high and low settings on them to control the amount of pressure retained. Later, there was something about gradual release, where the pressure would slowly bleed down. Are there different types of retainers, or am I full of you know what*?
* Misinformation
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(Edit): Never mind. I just re-read Al Krug's description.
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"A stranger's just a friend you ain't met yet." --- Dave Gardner
My basic knowledge of retainers comes from a now 54 year old Southern Asheville Division ETT, which, of course, had SPECIFIC instructions on the use of retainers in going down to Spartanburg from Asheville. Once all auxiliaries have been charged to 100 lbs,all retaining valve handles were to be turned up after the brakes were inspected--single pressure valves were to be turned all the way up, and double pressure handles were to be turned up to a 45 degree angle. Once the engine had pulled a sufficient distance over the crest, the engineer was to make a full service application of the dynamic brake and make several air brake applications--and then release immediately so as to fill the brake cylinders and retaining valve pipes. From time to time, brake applications were to be made to keep the train going slowly enough so that a 5 to 8 pound reduction would be able to stop the train. At the bottom of the grade, the retainers were to be turned down, and full a inspection of the train was to be made.
Instructions for descending certain grades between Asheville and Murphy, and descending from Ridgecrest to Old Fort if there is no dynamic brake operating are also given, but not in such detail; all retainer valves were to be turned up. Nothing was said about turning retainers down at the bottom of these grades.
There was no further discussion distinction between the use of single and double retainers.
Johnny
Johnny, you might have posted the link to the "Mountain of Challenge" video, which for all its endearing hokiness and Huckleberry Hound narration does specifically discuss how retainers were used going down Saluda (cf. 8:00).
The context of 'high' and 'low' retainers I remember had to do with dedicated sets of hopper cars in heavy service, which deserved (and perhaps needed) more 'retained set' loaded than empty. You'd still want some measure of reserved braking on empty trains or cuts, but the right amount to retard a loaded train might cause enhanced skidding or even increased risk of derailment or stringlining if applied to empties. Hence two distinct positions.
You can compare the difference between such a mechanism and the 'load sensing' devices on, say, some centerbeam flatcars that control direct braking effort depending on the truck-spring loading or whatever.
Yes; thanks, Overmod. I did not even think about that presentation of descending Saluda--which had been presented to us twice. I did not remember the specific application of the double retainers, and I trust that our op appreciates your description of their use. It is possible that no grain went down Saluda 54 years ago, so the doubles were not mentioned in those special instructions.
I should, perhaps, have added the further instruction concerning descending from Ridgecrest to Old Fort--if the dynamic brake is working properly, it is not necessary to turn retainers up--which saves a lot of time in getting over the road..
"I've read articles about the big CSX Sand Patch derailment. Some say the engineer did not brake frequently enough to keep snow/ice from building up between the shoes and the wheels. Others say he cycled the brakes too much and, and, as you say, pisssed away his air. Maybe this is simply a difference of opinion which endures. ??"
The brake applications to keep ice from building up on the brake shoes are done before you go over the top of the grade where you have time for the system to fully recharge before topping the hill. Releasing the air brakes while moving is not supposed to be done when descending the east side of Sand Patch.
Thanks all again.
Yes, earlier I meant to say “retainer.” (I am aware of car retarders in hump yards; years ago I used to go watch the action at Southern’s Inman Yard in Atlanta.)
quoted by mvlandsw"Some say the engineer did not brake frequently enough to keep snow/ice from building up between the shoes and the wheels. Others say he cycled the brakes too much and, and, as you say, pissed away his air.
I had thought it well-established that the 'cause' was outgassing from composition shoes, which over a critical speed (around 23mph on the relevant portion of the grade) prevent even a perfect air-brake system from physically holding the train. In that condition, the only thing that prevents a fairly rapid runaway (the outgassing effect only getting worse as momentum increases) would be dynamic braking -- which automatically disengages as emergency is applied; I believe units have to be equipped with a special 'key', as they were for Saluda Grade, that permits the dynamic to be kept on with a hard brake set (in conditions where skidding wheels is no longer an economic concern). Very likely only a small amount of additional acceleration will get you to the point that the number of axles of full dynamic that can be summoned up in the consist may not hold the train effectively either, even if sustained without skidding.
If I remember correctly the only thing the engineer 'did wrong' was assume the amount of dynamic he actually had working on his consist was sufficient to keep the train well below the 'critical speed'. By the time he realized that things weren't working right -- Katy, bar the door!
It is possible that union representatives or whoever would raise the 'ice on the brakeshoes' idea as a practical excuse for an accusation of poor train-handling judgment. But as noted, any icing would have been melted, and then kept from refreezing, by proper brake procedure prior to starting down the grade ... at least in proper practice.
mvlandsw"I've read articles about the big CSX Sand Patch derailment. Some say the engineer did not brake frequently enough to keep snow/ice from building up between the shoes and the wheels. Others say he cycled the brakes too much and, and, as you say, pisssed away his air. Maybe this is simply a difference of opinion which endures. ??" The brake applications to keep ice from building up on the brake shoes are done before you go over the top of the grade where you have time for the system to fully recharge before topping the hill. Releasing the air brakes while moving is not supposed to be done when descending the east side of Sand Patch.
The Sand Patch runaway of 2009 or 2010 (don't have total photographic memory recall) happened in the midst of at 20+ inch blizzard in the mid-Atlantic states. Leaving Connellsville, where a helper was attached, The Engineer expressed reservations about taking the train down the mountain under the conditions - the Asst. Division Manager instructed the Engineer to proceed. After the engineer made his first brake application after cresting Sand Patch he knew he wasn't getting the proper level of retardation and placed the train in emergency - and the tripping of the PC switch cut out dynamic braking on the locomotives. After that is was ride the train down the mountain. The locomotives made the descent, the cars all piled up. I don't know if the engineer, after placing the train in emergency attempted by any means to reactivate the dynamic braking on the engine consist.
At the time of this happening, the Baltimore Division Timetable for the Keystone Subdivision had no special instructions about conditioning the brakes to insure that the brake shoes were contacting the wheels, not blocks of ice built up on the brake shoes.
Operating in the same area was the Huntington Division's Mountain Subdivision between Cumberland and Grafton over 17 Mile Grade, Cranberry Grade and Cheat River Grade. The Huntington Division Timetable did have a special instruction requiring engineers to condition their brakes before descending any of the grades mentioned.
Subsequent to the incident, special instructions were implemented on the Keystone subdivision that mirrored those on the Mountain subdivision.
Never too old to have a happy childhood!
My first experience with retainers was back in 1954 when my high school class trip was to Washington DC from/to Cincinnati. On the westward trip on #1, i spent significant time in the vestible and remember the trainman comming through the car and operating a valve. Upon my query, he told me he was activating the RETAINER. Gave me a little discription of its function. We were somewhere west of Cumberland (having bypassed it) on the grades and of course, the B&O E units didn't have dynamic braking. It was dark and the sight of all the sparks from the brake shoes as the train snaked down the hills with the headlight lighting up the path and the train windows glowing is something I will never forget. The retainers allowed the engineer to retain braking while recharging the trainline and the reservoirs.
It may be an option that's railroad specific, but our locomotives have a Dynamic Brake Holding Feature. When the engineer places the automatic brake valve in emergency and the PCS opens, this feature keeps the dynamic brake operative. I think all our modern engines have it. The older power may not.
I think it was the instructor back in engineer's school at Salt Lake City who told us this. (He worked, when not instructing, mountain grade territory.) He said if you're going down grade and have to put the train in emergency and the PCS opens up killing the dynamics, to do this. Wait for the brake pipe to go to 0 and completely exhaust. Move the automatic brake handle from Emergency to Handle Off. This won't initiate a release, something you don't do until you're stopped, but will allow the PCS to reset. This restores dynamic braking capability.
He said it would work, but I'll probably never have the chance (nor do I want the chance) to try this. Most of our grades aren't that long.
Jeff
BaltACD mvlandsw "I've read articles about the big CSX Sand Patch derailment. Some say the engineer did not brake frequently enough to keep snow/ice from building up between the shoes and the wheels. Others say he cycled the brakes too much and, and, as you say, pisssed away his air. Maybe this is simply a difference of opinion which endures. ??" The brake applications to keep ice from building up on the brake shoes are done before you go over the top of the grade where you have time for the system to fully recharge before topping the hill. Releasing the air brakes while moving is not supposed to be done when descending the east side of Sand Patch. The Sand Patch runaway of 2009 or 2010 (don't have total photographic memory recall) happened in the midst of at 20+ inch blizzard in the mid-Atlantic states. Leaving Connellsville, where a helper was attached, The Engineer expressed reservations about taking the train down the mountain under the conditions - the Asst. Division Manager instructed the Engineer to proceed. After the engineer made his first brake application after cresting Sand Patch he knew he wasn't getting the proper level of retardation and placed the train in emergency - and the tripping of the PC switch cut out dynamic braking on the locomotives. After that is was ride the train down the mountain. The locomotives made the descent, the cars all piled up. I don't know if the engineer, after placing the train in emergency attempted by any means to reactivate the dynamic braking on the engine consist. At the time of this happening, the Baltimore Division Timetable for the Keystone Subdivision had no special instructions about conditioning the brakes to insure that the brake shoes were contacting the wheels, not blocks of ice built up on the brake shoes. Operating in the same area was the Huntington Division's Mountain Subdivision between Cumberland and Grafton over 17 Mile Grade, Cranberry Grade and Cheat River Grade. The Huntington Division Timetable did have a special instruction requiring engineers to condition their brakes before descending any of the grades mentioned. Subsequent to the incident, special instructions were implemented on the Keystone subdivision that mirrored those on the Mountain subdivision.
mvlandsw "I've read articles about the big CSX Sand Patch derailment. Some say the engineer did not brake frequently enough to keep snow/ice from building up between the shoes and the wheels. Others say he cycled the brakes too much and, and, as you say, pisssed away his air. Maybe this is simply a difference of opinion which endures. ??" The brake applications to keep ice from building up on the brake shoes are done before you go over the top of the grade where you have time for the system to fully recharge before topping the hill. Releasing the air brakes while moving is not supposed to be done when descending the east side of Sand Patch.
jeffhergert It may be an option that's railroad specific, but our locomotives have a Dynamic Brake Holding Feature. When the engineer places the automatic brake valve in emergency and the PCS opens, this feature keeps the dynamic brake operative. I think all our modern engines have it. The older power may not. Jeff
Using the jammer when the dynamics cut out was a rather insufficient replacement, but it was better than letting the slack run out, especially if you had multiple locomotives! (I always carried a 1/4" Allen wrench for those "special" occasions, especially in the yard)
zardoz jeffhergert It may be an option that's railroad specific, but our locomotives have a Dynamic Brake Holding Feature. When the engineer places the automatic brake valve in emergency and the PCS opens, this feature keeps the dynamic brake operative. I think all our modern engines have it. The older power may not. Jeff Jeff, the former CNW power did NOT have that feature (SD40-2 and earlier). Using the jammer when the dynamics cut out was a rather insufficient replacement, but it was better than letting the slack run out, especially if you had multiple locomotives! (I always carried a 1/4" Allen wrench for those "special" occasions, especially in the yard)
Jeff, the former CNW power did NOT have that feature (SD40-2 and earlier).
Note in the Saluda Grade video that the Road Foreman has a special key that when inserted and operated will keep the dynamics working when there is a emergency brake application.
When I was in Engineers school in Cumberland I asked the instructor if it wasn't a bad idea to eliminate dynamic braking when in emergency. It seemed like you would want to keep all braking power possible in an emergency situation. Some years later Chessie engines, or maybe it was CSX by then, were changed to retain dynamic braking in emergency.
They were set up that way by the time of the Sand Patch runaway.
"I think it was the instructor back in engineer's school at Salt Lake City who told us this. (He worked, when not instructing, mountain grade territory.) He said if you're going down grade and have to put the train in emergency and the PCS opens up killing the dynamics, to do this. Wait for the brake pipe to go to 0 and completely exhaust. Move the automatic brake handle from Emergency to Handle Off. This won't initiate a release, something you don't do until you're stopped, but will allow the PCS to reset. This restores dynamic braking capability.
He said it would work, but I'll probably never have the chance (nor do I want the chance) to try this. Most of our grades aren't that long. "
I discovered this once after stopping in emergency with the dynamic controller still in full on position. After the PCS reset the dynamic came back on, although without any load since the train wasn't moving. I later tried it with moving light engines and full dynamic brake control was indeed restored with the automatic brake pressure at zero.
jeffhergertWait for the brake pipe to go to 0 and completely exhaust. Move the automatic brake handle from Emergency to Handle Off.
Your basic reset after an emergency application. Do it every day I run while I'm doing my locomotive brake test (or if someone cuts in the consist too quickly after a runaround).
Every now and then the gauge looks like it reads zero, but there's still air moving, so moving the brake handle to handle off won't reset the PCS. In a situation such as we're discussing, it might be hard to muster up the patience to let the pipe fully exhaust, but until it does, you're not getting your reset.
If you go into emergency and the dynamic brakes cut out, can you still use the independent brake on the locomotives to help slow you down?
(Edit): Never mind. I realize that the locomotives are included in the emergency braking. I should have remembered this. The old mind seems to be going.
There is a timing reservoir on the PCS switch that must be exhausted before the engine will reset from PCS. But yes, if you wait a bit you can reset PCS and continue using the dynamic brakes without releasing the train.
This reservoir prevents fast cycling of the PCS switch, I think its 10-16 seconds delay.
Or you throw it in reverse ...
Ex-BNSF engineer raises safety concerns, claims wrongful terminationhttp://www.king5.com/article/news/local/ex-bnsf-engineer-raises-safety-concerns-claims-wrongful-termination/281-511346381
I think that potential technical issues with locomotive 2339 and its maintenance deserve their own thread - with some close inspection of the trial and its results when they occur.
Randy Stahl There is a timing reservoir on the PCS switch that must be exhausted before the engine will reset from PCS. But yes, if you wait a bit you can reset PCS and continue using the dynamic brakes without releasing the train. This reservoir prevents fast cycling of the PCS switch, I think its 10-16 seconds delay.
There was a way to beat an undesired penalty application too, but, I won't go into that here.
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