Paul Milenkovic bogie_engineer Euclid I believe there is a torque spec of 125 ft. lbs. As I stated earlier in this thread, the design is based on 125 lbs. force applied to rim of the handwheel or for lever type brakes, the gripping point on the lever. The designer has a range of lever lengths or hand wheel diameters, plus the gear ratio of the handbrake mechanism to translate that 125 lbs. force to sufficient force on the shoes to hold the car or loco on a 3% grade. A problem using an impact wrench to provide the torque is that it beats the crap out of the gearing and bearings in the handbrake unit. Dave 125 foot pounds by applying both hands to a 15 inch wheel?
bogie_engineer Euclid I believe there is a torque spec of 125 ft. lbs. As I stated earlier in this thread, the design is based on 125 lbs. force applied to rim of the handwheel or for lever type brakes, the gripping point on the lever. The designer has a range of lever lengths or hand wheel diameters, plus the gear ratio of the handbrake mechanism to translate that 125 lbs. force to sufficient force on the shoes to hold the car or loco on a 3% grade. A problem using an impact wrench to provide the torque is that it beats the crap out of the gearing and bearings in the handbrake unit. Dave
Euclid I believe there is a torque spec of 125 ft. lbs.
I believe there is a torque spec of 125 ft. lbs.
As I stated earlier in this thread, the design is based on 125 lbs. force applied to rim of the handwheel or for lever type brakes, the gripping point on the lever. The designer has a range of lever lengths or hand wheel diameters, plus the gear ratio of the handbrake mechanism to translate that 125 lbs. force to sufficient force on the shoes to hold the car or loco on a 3% grade.
A problem using an impact wrench to provide the torque is that it beats the crap out of the gearing and bearings in the handbrake unit.
Dave
125 foot pounds by applying both hands to a 15 inch wheel?
No, it's 125 lbs. force, not torque, applied to the lever or wheel rim, the resulting torque is a function of the lever length or diameter of the wheel. Internally, the handbrake unit has a gear train to multiply the torque produced and wind up the chain. The manufacturer states the gear ratio acting on the chain, the loco brake designer decides what diameter wheel to chose to get the needed chain force from the 125 lb. force applied. Doesn't matter how many hands are used to produce the 125 lb. force.
My experience is with locomotives, after researching the FRA and AAR standards for freight cars, the 22" diameter handbrake wheel is mandated on cars built since 1966. Regardless of whether it acts on one or both trucks, it has to produce a total force on the shoes that it acts on of 10% of the gross weight of the car, which using a composition shoe static coefficient of friction of 25%, results in a grade holding ability of 2.5%.
BaltACD SD70Dude jeffhergert * What is the PTC Park function you ask? When it's engaged, if it detects movement it will dump the air. We have a version of that called "roll-away protection" in Canada, though our feature is not part of PTC. American units must not have it, or that UP unit wouldn't have been able to run away earlier this year in Saskatchewan (it was a DP remote, and the crew forgot to set it out when the left it by itself and went to do some switching, so now we aren't allowed to "save the air" anymore). The CROR requires that we do a push/pull test whenever equipment is left on a grade, which is practically everywhere. Saving the air has been a no no in the US for decades.
SD70Dude jeffhergert * What is the PTC Park function you ask? When it's engaged, if it detects movement it will dump the air. We have a version of that called "roll-away protection" in Canada, though our feature is not part of PTC. American units must not have it, or that UP unit wouldn't have been able to run away earlier this year in Saskatchewan (it was a DP remote, and the crew forgot to set it out when the left it by itself and went to do some switching, so now we aren't allowed to "save the air" anymore). The CROR requires that we do a push/pull test whenever equipment is left on a grade, which is practically everywhere.
jeffhergert * What is the PTC Park function you ask? When it's engaged, if it detects movement it will dump the air.
* What is the PTC Park function you ask? When it's engaged, if it detects movement it will dump the air.
We have a version of that called "roll-away protection" in Canada, though our feature is not part of PTC. American units must not have it, or that UP unit wouldn't have been able to run away earlier this year in Saskatchewan (it was a DP remote, and the crew forgot to set it out when the left it by itself and went to do some switching, so now we aren't allowed to "save the air" anymore).
The CROR requires that we do a push/pull test whenever equipment is left on a grade, which is practically everywhere.
Saving the air has been a no no in the US for decades.
"Bottling the air" has been a no no for as long as anyone can remember.
"Saving the air" uses the DP remote's automatic brake valve to maintain the brake application on the train, just like any other lead locomotive. The DP remote will automatically put the train into emergency if it starts moving or detects signs of an unintentional release.
Greetings from Alberta
-an Articulate Malcontent
Never too old to have a happy childhood!
We don't use push/pull for our securement test. It's release all the air, both train and independent brake. If it moves, it needs more hand brakes. If it doesn't move, it's good to go, or good to stay.
Just did this today. 114 car coal train. Conductor tied what he thought was enough. It wasn't, then he tied some more. Second time was the charm. In addition to the hand brakes on cars and head end locomotive consist, left the train with a 20 lbs set and the PTC Park* feature engaged.
In regards to Euclid about minimum numbers. Instructions have changed every so often. It started with "sufficient number" then progressed to a certain percentage (the percentage depending on track and location) with a minimum of 5 cars on main tracks and sidings. Some yards did, and some still do, have a specific number minimum for tracks within the physical yard. Even with the minimum, whether specific number or percentage, it still required a securement test. Just in case for whatever reason, the prescribed amount didn't hold.
Now we're back to a sufficient number and then a securement test. That's our primary method. There is a secondary method that is to be used where the primary isn't practical. It involves using a chart, so many brakes for so many tons on specific grades. The steeper the grade, the more tons being left, the more hand brakes. You can be sure the chart will err on the side of overkill.
In the distant past, brakemen/switchmen carried brake clubs to help them apply/release hand brakes. Today's hand brakes don't need their use and it's prohibited to use brake clubs. (Note, there are tools in use called a brake stick, at least ours are, to allow tying hand brakes from the ground. They are not like, nor used like the brake clubs of the past.) The wheels are geared so that maximum force can be applied by just turning the wheel. Some may be able to get a few "clicks" out of the brake wheel when tightening it up, but unless there is a mechanical problem anyone tying the hand brake should be able to get it to where it works as intended.
Jeff
And yet trains don't run away each and every day, despite regularly being left unattended outside of yards.
Overmod Euclid As I mentioned, as incredible as it may seem, there is no practical way to secure a train and know that it will stay put.
Euclid As I mentioned, as incredible as it may seem, there is no practical way to secure a train and know that it will stay put.
Just to be clear: When I said, "there is no practical way to secure a train and know that it will stay put," I was using the word "is" to refer to present day practice. I did not mean that the securement solution is simply impossible to achieve. I meant that securement is impossible to achieve with today's practice.
I am fully aware that there may be a thousand solutions that could make it possible if they were developed and purchased by the railroads. The problem is not a lack of technology or expertise. The problem is that progress in this area has not been pursued by the industry.
But that alone is rather shocking I think, and that is the only point I am making. No way to safely secure a freight train exists in current practice today. You can find the references to that claim in the TSB report on the QNS&L runaway.
Overmod Perhaps there could be a rapidly-accessible screen for 'brake testing' that would contain the display together with confirmation that both the automatic and independent were off ... and log the result for posterity.
Perhaps there could be a rapidly-accessible screen for 'brake testing' that would contain the display together with confirmation that both the automatic and independent were off ... and log the result for posterity.
In theory that is a pretty good idea.
In reality it would just be used as another 'efficiency test', I can already see certain supervisors looking at the download and accusing the crew of doing an improper test because they only pulled/pushed for 9.5 seconds instead of the required 10, or other such things (we get downloaded enough already).
The vast majority of the problems with air and handbrake effectiveness could be fixed with proper maintenance, and the proper enforcement of maintenance standards by the regulators. But I'm not holding my breath.
I suspect the railroads won't be thrilled at the idea of installing brake pressure sensors, just like their reaction to the proposed ECP mandate.
SD70DudeI don't think a drawbar strain gauge is necessary, one could simply measure the tractive effort produced by the locomotive(s) during the push/pull test.
Strain gauges already exist to measure the pressure between brake shoes and wheels, though the Car Department does not use them nearly as often as they probably should.
Right on the brake shoe is the only place a sensor could be placed to ensure an accurate measurement, the amount of force applied to the brake wheel or lever does not necessarily translate into braking effort if the moving parts are rusty, stiff, or seized (I've seen many wheels that won't turn at all), or if the chain or rigging is disconnected or jammed somewhere underneath the car.
I don't think a drawbar strain gauge is necessary, one could simply measure the tractive effort produced by the locomotive(s) during the push/pull test.
EuclidAs I mentioned, as incredible as it may seem, there is no practical way to secure a train and know that it will stay put.
I am not quite certain why there was not a parallel or codicil to the Power Brake Law that formalized systems of securement brake. Certainly it's within the Government 'remit' of safety, and even something like a yearly requirement to check lubrication and adjustment would have solved most of the securement-related issues. A good law would also clarify things like whether 'a handbrake' is all eight wheels on a car without foundation braking, or whether braking should be measured by truck or axle in versions of the 'tables' so far written in blood. Perhaps this ought to be low-hanging fruit for a Biden FRA; had I applied for that Director of Safety job a couple of months ago, it might be an early priority...
A simple handheld test gage (a couple of strain gages in a curved frame would do it) applied between wheel and shoe gives a direct reading of applied pressure; comparably instrumented gloves will give a direct pull reading whether wheel or lever, and also 'catch' some forms of gearbox or ratchet damage over the range of application. If we add power application to a gearbox, a simple torquemeter arrangement does the same with added precision related to device position, and would allow more cars to be inspected per hour with much lower fatigue than winding on. Scan in the car number and any related data and you have a quick and easy test at any time ... then automate an event ticket for the carman's union or whatever.
For application assurance, the issue is a bit more involved, although if you have reasonable assurance most of the cars in your consist have been 'blue-carded' within the past year it's a bit less urgent.
The only real indicator of securement is a passive mechanical indicator that reads physical pressure between shoe and wheel. (It can of course actually 'read' elsewhere in the part of the brake rigging close to the shoe ... but in any case closer than any slack adjuster, which might pose some interesting concerns for TMB. In my opinion this should also include a couple of redundant strain gages (and their associated 'connectivity') but that's for the age of instrumented cars, which lies in the undiscovered country on the other side of ECP implementation -- don't hold your breath for it any time soon. Ideally this would be a spring indicator with a red end that protrudes only when a good set exists between shoe and wheel, without regard for any slack that might have developed or any wear in the shoe or other components since new. The indicator should not fail in any way that impairs braking, ruins the shoe or the wheeltread, etc. etc. etc. -- this would be an ideal thing for Euclid to pass his time designing.
This takes care of the first two points; the corrected 'standard' table we wind up adopting nationwide takes care of the fourth. That leaves us with an effective procedure for securement testing, and I just can't help thinking that a good push/pull test with an instrumented gage at the trailing coupler face of the consist would do that nicely. Put it between knuckles to test pull; put it between buffing faces to test push; then take it out and put it in your grip... we assume this is tested, like my control for 'automated' penalty freight braking, on the same kind of schedule as a railroad watch, with the same distribution of responsibility.
Keeping a train from rolling away on a grade when there are brakes on each axle seems like a rather easy exercise, if you use a little common sense in ensuring simple things work as expected. Whether they are Civil-War primitive as constructed or encountered, or not.
EuclidAs I mentioned, as incredible as it may seem, there is no practical way to secure a train and know that it will stay put. This makes my point about using Civil War era technology in 2020. This is due the following: No way to know how much torque is being applied. No way to know if brake is working properly to transmit the torque applied. No way to test the securement once applied. No way to know how many properly applied brakes it takes to reliably secure the train.
No way to know how much torque is being applied.
No way to know if brake is working properly to transmit the torque applied.
No way to test the securement once applied.
No way to know how many properly applied brakes it takes to reliably secure the train.
Just as there is no way to secure Euclid in place - hand brakes, air brakes, dive brakes, independent brakes, skates, chocks, ABS, CTC, TWC, PTC or any other invention known to humankind.
As I mentioned, as incredible as it may seem, there is no practical way to secure a train and know that it will stay put. This makes my point about using Civil War era technology in 2020. This is due the following:
That is like trying to remove a stuck lug nut with a "star" lug wrench. Is there a fitness requirement for serving on a train crew?
That is why I know carry a breaker bar in my trunk with an impact socket sized to the lug nut of the car I am driving. With a breaker bar, I can put my 190 pounds of bone, muscle and flab into it, generating over 500 foot pounds if needed. I don't think I could ever crank on a 15 inch brake wheel to reach 125 foot pounds.
By the way, there are numerous Internet posts on a thing called a "torque" multiplier -- it works when a breaker bar fails. It does not involve hammering impacts, but it uses a gear reduction. It does, however, require a fulcrum for its reaction bar, otherwise this thing would be like "pulling yourself up by your own bootstraps."
If GM "killed the electric car", what am I doing standing next to an EV-1, a half a block from the WSOR tracks?
A feature like found on a torque wrench that clicks when the proper torque is attained is definitely the key feature that is missing from railcar hand brakes. I would speculate that there are hundreds of patents on just such a feature. Without such a “set” indicator, the task is left to the operator, and the tighter the set, the more work the securement is.
I believe there is a torque spec of 125 ft. lbs. That might be even mentioned in the TSB report of the QNS&L runaway. But if a person is given no means of knowing what force they are applying, nothing is holding their feet to fire to sufficiently tighten the brake. And people are inclined to not work any harder than they have to. Anyone can look at the car and see that a hand brake is applied, but nobody can look at it and tell how tightly it is applied.
So there are two problems concerning setting of handbrakes:
The need to have the brake mechanism properly maintained.
The need to apply enough force in the brake application.
There is also this problem: Rules specify a number of handbrakes required only as being a minimum. There is no guarantee that the minimum specified will be enough to hold the train.
What the industry has opted to do in lieu of a torque indicator is to use the practical method known as the push/pull test after handbrakes are applied. With this test, you just push and pull on the train after handbrakes are set, and make a practical judgement as to how much brake retardation actually exists from the set handbrakes.
But then there is this: The TSB has publically stated that the push/pull test is NOT a reliable indicator of handbrake holding power when the test is performed on relatively steep, mountain grades.
Therefore, in the end, the TSB leaves the task of handbrake securement entirely up to the experience and judgement of the employees doing the work. So the system in use today is exactly the same as the system in use during the Civil War, except for some improvements to the winch.
Paul Milenkovic BaltACD Paul Milenkovic Another idea along those lines would be for train crew to use an electric impact/torque wrench? I am probably telling people around here stuff that they already know, but I bought a "breaker bar" in order to loosen bolts on a brake caliper frame in order to change brake rotors on a car, and I am figuring I am going to need a lot more torque than that if I take on the challenge of changing the rear struts on an old car that is bouncing pretty good. An air tool impact wrench would be the next step up, and a biochemist turned computer support guy at the U who works on his own cars told me "get yourself a good air compressor", but I have a neighbor whose son works professionally as an auto mechanic who showed me an electric impact wrench he uses for fixing his Dad's pickup truck. A heavy-duty electric impact wrench runs at least several hundred dollars so I am holding off on getting one until I really need it. But a breaker bar looks like it has more mechanical advantage than a brake wheel, and one of those gee-whiz lithium battery super-powerful permanent magnet electric motor impact wrench has specs that outdo my 36" breaker bar? So yes they are expensive, and yes you have to keep a battery charged, but would one of those hand-held electric impact wrenches with a torque setting be the thing to crank down brake wheels? The other thing about these impact wrenches is that they have some kind of mass-reaction thing in them that you don't need to be exceptionally strong to use one, or at least so they tell me. They also apply rapid hammer pulses that they free up stuck bolts? Would this work on a creaky brake wheel? In a word - NO A impact wrench would be attempting to apply torque at the point that is least effective to transmit that torque to a machine - the pivot point of the machine. The hand brake wheel provides a mechanical advantate of a foot to 15 inches in applying torque to the pivot point. If you want to view some of the trials and tribulations of performing routine maintenance are repairs to cars that have been off the assembly line for a number of years and operating in a less than hospitable enviornment may I sugges viewing the 'South Main Auto Channel' on YouTube https://www.youtube.com/channel/UCtAGzm9e_liY7ko1PBhzTHA I guess a "no" in capital letters from someone with both automotive and railroad experience clinches it? If I may raise one more, small point, as someone in the Ivory Tower with no railroad experience and limited car-repair experience, the 12-15 inches of mechanical advantage of a brake wheel is a kind of a wrench handle. The force applied by a crew member'a hands to the rim of the brake wheel is transmitted through the resulting torque applied to brake wheel shaft that is in turn transmitted through a multiplicity of chains and links to force of the brake shoes against the wheels. A torque is a torque, and the laws of Classical Mechanics do not care if that torque is directly applied to the brake wheel shaft by some apparatus or if it is applied to that shaft through a type of wrench handle (the brake wheel spokes connecting the brake wheel rim to the shaft). Now one of those impact wrench devices is one of life's mysteries, as to how this device without any lever arm to speak of can apply anywhere near the torque of a long breaker-bar handle. It is also a mystery to me because I have never taken one apart, but my understanding is there is a kind of Newton's law "every action has an equal-and-opposite reaction" where the action applied by the impact wrench chuck is opposed by a reaction of some kind of flywheel internal to this device. The specs of a high-end hand-held impact wrench exceed what my wimpy research engineer self can apply at the end of a long breaker bar. I am also aware that one can tighten up a brake wheel two-handed, and in that way it is like one of those "star" wrenches for loosening lug nuts, and I still have mine I purchased from Pep Boys on Colorado Boulevard when I was a pencil-necked graduate student at a certain institution of higher learning in the foothills of the Los Angeles San Gabriel mountains some forty years ago, but I have never had luck with that thing -- that is why I purchased the breaker bar to which I can apply the 40 pounds of weight I have gained since that time by leaning on it. A person could tell railroad-ignorant me that a freight car brake wheel lacks an exposed central hub to which a socket chucked into an impact wrench could do its thing, and I "get" that retrofitting the freight-car fleet with such a hub. For this picture https://www.bing.com/images/search?view=detailV2&ccid=eGNH5UD2&id=9A740E36AE709BF8DA210535D6A52FAB50A3B229&thid=OIP.eGNH5UD26C6bftklSRRGsAHaLJ&mediaurl=https%3a%2f%2fmedia.istockphoto.com%2fphotos%2frusted-train-brake-wheel-picture-id658011652&exph=1024&expw=680&q=Train+Brake+Wheel&simid=607988698847055615&ck=022874EA9E06633251BABE4C649AA008&selectedIndex=77&FORM=IRPRST&ajaxhist=0 it appears that applying the wrench to the nut at the hub to tighten the brake wheel would have the effect for removing the nut holding the brake wheel on? I am just saying that if there were a place to apply the impact wrench, it is spec'ed with multiples of the torque that I could ever apply to a 15 inch hand brake wheel.
BaltACD Paul Milenkovic Another idea along those lines would be for train crew to use an electric impact/torque wrench? I am probably telling people around here stuff that they already know, but I bought a "breaker bar" in order to loosen bolts on a brake caliper frame in order to change brake rotors on a car, and I am figuring I am going to need a lot more torque than that if I take on the challenge of changing the rear struts on an old car that is bouncing pretty good. An air tool impact wrench would be the next step up, and a biochemist turned computer support guy at the U who works on his own cars told me "get yourself a good air compressor", but I have a neighbor whose son works professionally as an auto mechanic who showed me an electric impact wrench he uses for fixing his Dad's pickup truck. A heavy-duty electric impact wrench runs at least several hundred dollars so I am holding off on getting one until I really need it. But a breaker bar looks like it has more mechanical advantage than a brake wheel, and one of those gee-whiz lithium battery super-powerful permanent magnet electric motor impact wrench has specs that outdo my 36" breaker bar? So yes they are expensive, and yes you have to keep a battery charged, but would one of those hand-held electric impact wrenches with a torque setting be the thing to crank down brake wheels? The other thing about these impact wrenches is that they have some kind of mass-reaction thing in them that you don't need to be exceptionally strong to use one, or at least so they tell me. They also apply rapid hammer pulses that they free up stuck bolts? Would this work on a creaky brake wheel? In a word - NO A impact wrench would be attempting to apply torque at the point that is least effective to transmit that torque to a machine - the pivot point of the machine. The hand brake wheel provides a mechanical advantate of a foot to 15 inches in applying torque to the pivot point. If you want to view some of the trials and tribulations of performing routine maintenance are repairs to cars that have been off the assembly line for a number of years and operating in a less than hospitable enviornment may I sugges viewing the 'South Main Auto Channel' on YouTube https://www.youtube.com/channel/UCtAGzm9e_liY7ko1PBhzTHA
Paul Milenkovic Another idea along those lines would be for train crew to use an electric impact/torque wrench? I am probably telling people around here stuff that they already know, but I bought a "breaker bar" in order to loosen bolts on a brake caliper frame in order to change brake rotors on a car, and I am figuring I am going to need a lot more torque than that if I take on the challenge of changing the rear struts on an old car that is bouncing pretty good. An air tool impact wrench would be the next step up, and a biochemist turned computer support guy at the U who works on his own cars told me "get yourself a good air compressor", but I have a neighbor whose son works professionally as an auto mechanic who showed me an electric impact wrench he uses for fixing his Dad's pickup truck. A heavy-duty electric impact wrench runs at least several hundred dollars so I am holding off on getting one until I really need it. But a breaker bar looks like it has more mechanical advantage than a brake wheel, and one of those gee-whiz lithium battery super-powerful permanent magnet electric motor impact wrench has specs that outdo my 36" breaker bar? So yes they are expensive, and yes you have to keep a battery charged, but would one of those hand-held electric impact wrenches with a torque setting be the thing to crank down brake wheels? The other thing about these impact wrenches is that they have some kind of mass-reaction thing in them that you don't need to be exceptionally strong to use one, or at least so they tell me. They also apply rapid hammer pulses that they free up stuck bolts? Would this work on a creaky brake wheel?
I am probably telling people around here stuff that they already know, but I bought a "breaker bar" in order to loosen bolts on a brake caliper frame in order to change brake rotors on a car, and I am figuring I am going to need a lot more torque than that if I take on the challenge of changing the rear struts on an old car that is bouncing pretty good.
An air tool impact wrench would be the next step up, and a biochemist turned computer support guy at the U who works on his own cars told me "get yourself a good air compressor", but I have a neighbor whose son works professionally as an auto mechanic who showed me an electric impact wrench he uses for fixing his Dad's pickup truck.
A heavy-duty electric impact wrench runs at least several hundred dollars so I am holding off on getting one until I really need it. But a breaker bar looks like it has more mechanical advantage than a brake wheel, and one of those gee-whiz lithium battery super-powerful permanent magnet electric motor impact wrench has specs that outdo my 36" breaker bar?
So yes they are expensive, and yes you have to keep a battery charged, but would one of those hand-held electric impact wrenches with a torque setting be the thing to crank down brake wheels?
The other thing about these impact wrenches is that they have some kind of mass-reaction thing in them that you don't need to be exceptionally strong to use one, or at least so they tell me. They also apply rapid hammer pulses that they free up stuck bolts?
Would this work on a creaky brake wheel?
In a word - NO
A impact wrench would be attempting to apply torque at the point that is least effective to transmit that torque to a machine - the pivot point of the machine. The hand brake wheel provides a mechanical advantate of a foot to 15 inches in applying torque to the pivot point.
If you want to view some of the trials and tribulations of performing routine maintenance are repairs to cars that have been off the assembly line for a number of years and operating in a less than hospitable enviornment may I sugges viewing the 'South Main Auto Channel' on YouTube https://www.youtube.com/channel/UCtAGzm9e_liY7ko1PBhzTHA
I guess a "no" in capital letters from someone with both automotive and railroad experience clinches it?
If I may raise one more, small point, as someone in the Ivory Tower with no railroad experience and limited car-repair experience, the 12-15 inches of mechanical advantage of a brake wheel is a kind of a wrench handle. The force applied by a crew member'a hands to the rim of the brake wheel is transmitted through the resulting torque applied to brake wheel shaft that is in turn transmitted through a multiplicity of chains and links to force of the brake shoes against the wheels.
A torque is a torque, and the laws of Classical Mechanics do not care if that torque is directly applied to the brake wheel shaft by some apparatus or if it is applied to that shaft through a type of wrench handle (the brake wheel spokes connecting the brake wheel rim to the shaft).
Now one of those impact wrench devices is one of life's mysteries, as to how this device without any lever arm to speak of can apply anywhere near the torque of a long breaker-bar handle. It is also a mystery to me because I have never taken one apart, but my understanding is there is a kind of Newton's law "every action has an equal-and-opposite reaction" where the action applied by the impact wrench chuck is opposed by a reaction of some kind of flywheel internal to this device.
The specs of a high-end hand-held impact wrench exceed what my wimpy research engineer self can apply at the end of a long breaker bar. I am also aware that one can tighten up a brake wheel two-handed, and in that way it is like one of those "star" wrenches for loosening lug nuts, and I still have mine I purchased from Pep Boys on Colorado Boulevard when I was a pencil-necked graduate student at a certain institution of higher learning in the foothills of the Los Angeles San Gabriel mountains some forty years ago, but I have never had luck with that thing -- that is why I purchased the breaker bar to which I can apply the 40 pounds of weight I have gained since that time by leaning on it.
A person could tell railroad-ignorant me that a freight car brake wheel lacks an exposed central hub to which a socket chucked into an impact wrench could do its thing, and I "get" that retrofitting the freight-car fleet with such a hub. For this picture
https://www.bing.com/images/search?view=detailV2&ccid=eGNH5UD2&id=9A740E36AE709BF8DA210535D6A52FAB50A3B229&thid=OIP.eGNH5UD26C6bftklSRRGsAHaLJ&mediaurl=https%3a%2f%2fmedia.istockphoto.com%2fphotos%2frusted-train-brake-wheel-picture-id658011652&exph=1024&expw=680&q=Train+Brake+Wheel&simid=607988698847055615&ck=022874EA9E06633251BABE4C649AA008&selectedIndex=77&FORM=IRPRST&ajaxhist=0
it appears that applying the wrench to the nut at the hub to tighten the brake wheel would have the effect for removing the nut holding the brake wheel on?
I am just saying that if there were a place to apply the impact wrench, it is spec'ed with multiples of the torque that I could ever apply to a 15 inch hand brake wheel.
A impact wrench requires a power supply - a power supply that has a finite capacity. Battery Operated impact wrenchs seen in common use these days have a maximum output in the 200/300 Ft.Lb range. Pneumatic operated impact wrenches have a higher output. How big of a battery pack and/or air tank would on have to carry to adequately tighten 75 hand brakes? How much maintenance would the mechanism's that impact wrenches would operate require? What happens when there is an need for 'hand brakes' and the torque applying devices are either not available or have exhausted their power supplies?
The more complexity one applies to a situation, the higher the risk of failure in that situation.
KISS
SD70Dude Also of note, on most of these cars the handbrake only applies on the B-end truck, as there is no brake rigging linking the two trucks together. So even if those 35 handbrakes were working properly they might have only given half the braking effort expected by the engineer.
Also of note, on most of these cars the handbrake only applies on the B-end truck, as there is no brake rigging linking the two trucks together. So even if those 35 handbrakes were working properly they might have only given half the braking effort expected by the engineer.
One service unit (division on other railroads) put out in their site specific securement instructions that those type airbrake system counted as 1/2 car. So if the instructions specified that a particular train would need 7 handbrakes and all you had were these types of cars, you would need to apply 14 handbrakes to meet the requirement.
Thservice unit my home terminal was on didn't have that 1/2 car specification. We were merged into the SU that did, with them taking control. Their instructions now ruled us, too. I attended a safety class where I mentioned this fact because a lot of people weren't aware of the change or requirement. Including a couple of local officers in attendence.
Me and my big mouth. Now I gave the company officers something else to check crews on when doing securement checks on tied down trains.
Most truck-mounted air brakes have two opposing pistons, though some designs could be different.
I wonder how many cars leaked off before the engineer applied their handbrakes?
Overmod - Carmen doing air tests from inside a moving vehicle has been a issue for years, the Companies say it is ok and Transport Canada lets them get away with it. But in my experience those "brake tests" are about as accurate as one would expect.
Paul MilenkovicAnother idea along those lines would be for train crew to use an electric impact/torque wrench? I am probably telling people around here stuff that they already know, but I bought a "breaker bar" in order to loosen bolts on a brake caliper frame in order to change brake rotors on a car, and I am figuring I am going to need a lot more torque than that if I take on the challenge of changing the rear struts on an old car that is bouncing pretty good. An air tool impact wrench would be the next step up, and a biochemist turned computer support guy at the U who works on his own cars told me "get yourself a good air compressor", but I have a neighbor whose son works professionally as an auto mechanic who showed me an electric impact wrench he uses for fixing his Dad's pickup truck. A heavy-duty electric impact wrench runs at least several hundred dollars so I am holding off on getting one until I really need it. But a breaker bar looks like it has more mechanical advantage than a brake wheel, and one of those gee-whiz lithium battery super-powerful permanent magnet electric motor impact wrench has specs that outdo my 36" breaker bar? So yes they are expensive, and yes you have to keep a battery charged, but would one of those hand-held electric impact wrenches with a torque setting be the thing to crank down brake wheels? The other thing about these impact wrenches is that they have some kind of mass-reaction thing in them that you don't need to be exceptionally strong to use one, or at least so they tell me. They also apply rapid hammer pulses that they free up stuck bolts? Would this work on a creaky brake wheel?
Another idea along those lines would be for train crew to use an electric impact/torque wrench?
Paul Milenkovic Could there be some kind of brake wheel club tool that would do this so it would not have to be retrofited to every freight car and locomotive?
Recall that there are two types of hand brake "activators." There are brake wheels, as noted, and there are levers. A calibrated brake club would have to be able to measure both.
Then there is the question of how much torque is enough. It may well vary by type of car, and how much of an application is on the brake pipe.
If I crank away at the lever on our passenger cars, with the brakes released, I can pull until I can't any more, and that's quite a bit. If the engineer then sets the brakes, I can usually get a couple more pulls in.
The same is true on our cars with brake wheels.
Retrofitting such a measuring device on every car not only introduces the cost of the installation, but the cost of the maintenance. Then we're into cost vs benefit.
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...
Euclid Regarding this QNS&L runaway, I see the following points in play: Poorly maintained air brake cylinders left them unable to hold pressure to maintain their application force. Poorly maintained hand brakes left them unable to provide clear operational feedback to the person applying them, and unable to provide application force that matches the application force indicated by the operational feedback. Even with perfectly operational handbrakes providing application force matching the feedback to the person setting them, there is no way to know for sure whether the person applying them is using enough manual force to make them fully effective. There are also no set criteria or rules specifying how many properly set handbrakes in good operating condition are required to assure the train is secured from possible movement. There is no effective test to determine whether the number of handbrakes set will be sufficient to assure the train is secured from possible movement. The technology of freight train brakes is essentially frozen due to upgrades needing to be compatible with all non-upgraded cars in the national loose car pool. While the brake technology is frozen, the performance needs for braking have increased due to trains becoming longer and heavier. The ability to compensate for the increased needs of longer/heavier trains is therefore increasingly limited, and thus more likely to fail.
Regarding this QNS&L runaway, I see the following points in play:
Poorly maintained air brake cylinders left them unable to hold pressure to maintain their application force.
Poorly maintained hand brakes left them unable to provide clear operational feedback to the person applying them, and unable to provide application force that matches the application force indicated by the operational feedback.
Even with perfectly operational handbrakes providing application force matching the feedback to the person setting them, there is no way to know for sure whether the person applying them is using enough manual force to make them fully effective.
There are also no set criteria or rules specifying how many properly set handbrakes in good operating condition are required to assure the train is secured from possible movement.
There is no effective test to determine whether the number of handbrakes set will be sufficient to assure the train is secured from possible movement.
The technology of freight train brakes is essentially frozen due to upgrades needing to be compatible with all non-upgraded cars in the national loose car pool.
While the brake technology is frozen, the performance needs for braking have increased due to trains becoming longer and heavier. The ability to compensate for the increased needs of longer/heavier trains is therefore increasingly limited, and thus more likely to fail.
If I have to take a wheel off to perform maintenance on my car, I use a torque wrench to tighten the lug nuts after putting a wheel back on. A torque wrench is essential if you have aluminum wheels, but I now use it on a car with steel wheels after the scare of a lug nut coming off in service.
The torque wrench I use is the kind where you turn a knob in the handle to set the desired torque level -- it has a Vernier arrangement that you can specify the torque to the nearest foot pound if you have good eyesight for reading the scale -- and you apply torque until you hear the wrench "click." This doesn't prevent applying more torque if one wanted to for good measure, but the click tells me I have tightened a nut enough. The wheel is good when I go through all five nuts in a pattern and hear "click, click, click, click, click."
Yeah, yeah and yeah, maintenance practices and friction and all of that, but could someone come up with some kind of clicker to indicate when a train crew member has cranked down hard enough on a hand-brake wheel? Could there be some kind of brake wheel club tool that would do this so it would not have to be retrofited to every freight car and locomotive?
Overmod The report says four cylinders per truck. I am not familiar with that detail design but hesitate to call them liars. I suspect the design is related to the three-piece construction.
The report says four cylinders per truck. I am not familiar with that detail design but hesitate to call them liars. I suspect the design is related to the three-piece construction.
No it implies that, but does not say that. It says, "LIM cars are equipped with truck mounted brakes that consist of four cylinders.
That could mean four cylinders per truck, but I believe it actually means two cylinders per truck, four total on the car. Each cylinder operating a brake beam for an individual wheelset on the trucks.
Convicted OneI'd post a picture of the Tulip Trestle for reference, but I do not own the rights to any such picture and I don't want the teacher to have a fit and give me a detention over I.P. sensitivities.
You can see on Google Maps, views of it.
https://www.google.com/maps/@39.0742372,-86.8539179,3a,75y,11.44h,98.48t/data=!3m7!1e1!3m5!1smh7hfra88WEWnHlW1S2uRw!2e0!6s%2F%2Fgeo0.ggpht.com%2Fcbk%3Fpanoid%3Dmh7hfra88WEWnHlW1S2uRw%26output%3Dthumbnail%26cb_client%3Dmaps_sv.tactile.gps%26thumb%3D2%26w%3D203%26h%3D100%26yaw%3D81.95169%26pitch%3D0%26thumbfov%3D100!7i13312!8i6656
EuclidWhile the brake technology is frozen, the performance needs for braking have increased due to trains becoming longer and heavier. The ability to compensate for the increased needs of longer/heavier trains is therefore increasingly limited, and thus more likely to fail.
I completly agree with you with the additional thought that with the current emphisis on reducing Operating Ratio pushing management to "cut costs", attention to maintenance and repair is reduced so the probability of more events like these seems inevitable.
Does it? C&P from the report:
LIM cars are equipped with truck-mounted brakes that consist of 4 brake cylinders.
I read that as four cylinders per car.
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