CMSTPP wrote: rjemery wrote: In another thread, an off topic discussion has begun about braking and breaking drawbars.What is a drawbar? If it is nothing more than a standard coupler, why is it referred to as a drawbar?When stopping or starting a typical freight train, what does the engineer need to do relevant to slack and preventing damage to the couplers?Ya the drawbar would be the coupler. But the reason behind that term I do not know. I could guess for you. The pin which holds the drawbar in place is the piece that moves. When coupling the drawbar can open up when the pin is lifted. So I would guess they call it that because it's the movable piece in the coupler. Someone else can probably better explain it than I did.When starting with the train, the engineer pulls the slack out of the train slowly. notch it up to one and back to idle. When the whole train has started to move then you can really notch up on it and get it going. when slowing down I have seen a lot of engineers bring it down with the automatic and just before they stop slowly start releasing it to ease the train to a stop with out that slack action kicking in. I have also seen (done on small trains) the engineer apply the automatic and just before they stop release it and apply the independent. If you know what your doing, that works well with smaller trains.James
rjemery wrote: In another thread, an off topic discussion has begun about braking and breaking drawbars.What is a drawbar? If it is nothing more than a standard coupler, why is it referred to as a drawbar?When stopping or starting a typical freight train, what does the engineer need to do relevant to slack and preventing damage to the couplers?
In another thread, an off topic discussion has begun about braking and breaking drawbars.
What is a drawbar? If it is nothing more than a standard coupler, why is it referred to as a drawbar?
When stopping or starting a typical freight train, what does the engineer need to do relevant to slack and preventing damage to the couplers?
Ya the drawbar would be the coupler. But the reason behind that term I do not know. I could guess for you. The pin which holds the drawbar in place is the piece that moves. When coupling the drawbar can open up when the pin is lifted. So I would guess they call it that because it's the movable piece in the coupler. Someone else can probably better explain it than I did.
When starting with the train, the engineer pulls the slack out of the train slowly. notch it up to one and back to idle. When the whole train has started to move then you can really notch up on it and get it going. when slowing down I have seen a lot of engineers bring it down with the automatic and just before they stop slowly start releasing it to ease the train to a stop with out that slack action kicking in. I have also seen (done on small trains) the engineer apply the automatic and just before they stop release it and apply the independent. If you know what your doing, that works well with smaller trains.
James
If you get a notch then release it trying to streach a train you can and most likly will get a knuckle. and it will probley happen around 15-25 cars deep. get a notch and keep pulling on GE engines i get 2 notches they load so slow they wont break anything right away. but most generaly a engineer will pull up to a stop streached. it is so much easier to get going.
Then there is the pic of a dip . id be pulling in 5-6 maybe 7 depending on my speed. keep them streached out. also if the slck does run in your pulling it out before the rear sets down on ya. microsoft simulator is a game what you do there isnt real world. not even close. a real good reason for applying brakes and pulling to a stop is to keep train tight so nobody can cut you in the bad neighbor hoods we go thru. i only release the brakes when i have been given permission to go and then i am pulling while brakes are releasing so they still cant cut me.
When it comes to blaming the track route and alignment for train handling problems one important thing is worth remembering. For the most part, all Class I routes were laid out and surveyed in the 19th Century by surveyors and rodman on horse back who did not have the benefit of accurate topographical maps, unless they made them, while traversing territories that for the most part were totally unknown to them. They laid out the routes understanding that the heaviest earth moving equipment available was the biggest Irish or German immigrant and the pick and shovel they used. Black Powder was the blasting agent of the time.
The trains that they were laying out the alignment for, would be considered laughably small and maddeningly slow by today's standards; there was no way that they could ever conceive of 20000 ton coal trains and 9000 foot and larger merchandise and intermodal trains all moving at speeds of 50-70 MPH. The fact that these 19th Century route alignments are still in use, for the most part, in the 21st Century speaks volumes about just how well the performed their task.
Never too old to have a happy childhood!
On coal, grain or ore trains I prefer to have slack stretched as it is a whole lot better to start the entire train at the same time, and their is a less of a chance to get a knuckle it seams that every time I get held at a control point I am always going up hill. The reason I prefer this methode is the knuckles are already loaded up.
Rodney
zardoz wrote: CMSTPP wrote: When starting with the train, the engineer pulls the slack out of the train slowly. notch it up to one and back to idle. When the whole train has started to move then you can really notch up on it and get it going. when slowing down I have seen a lot of engineers bring it down with the automatic and just before they stop slowly start releasing it to ease the train to a stop with out that slack action kicking in. I have also seen (done on small trains) the engineer apply the automatic and just before they stop release it and apply the independent. If you know what your doing, that works well with smaller trains.JamesI hope you are refering to Train Simulator when you describe that sort of train handling. The braking method you described is actually one of the easier way to break a drawbar. Was that a new engineer you were refering to? I ask because if he had some whiskers (seniority), and was running back when there were cabooses on trains, handling a train that way, he would have put the conductor in the hospital within a week.And you cannot "slowly" release the train brakes, unless the locomotive automatic brake valve is equipped with the 'graduated release" feature. This feature is usually only found on locomotives that might be used in passenger service (ie: CNW's F7s and E8's). I have frequently been amazed when I see extracted (by poor train-handling) drawbars lying on the ground with the knuckle still intact. Normally, you would think that the knuckle would give out long before the drawbar. However, usually there is quite a bit of rust on the face of the drawbar where the break occurred (indicating that the drawbar had been cracked for some time prior to the actual break).
CMSTPP wrote: When starting with the train, the engineer pulls the slack out of the train slowly. notch it up to one and back to idle. When the whole train has started to move then you can really notch up on it and get it going. when slowing down I have seen a lot of engineers bring it down with the automatic and just before they stop slowly start releasing it to ease the train to a stop with out that slack action kicking in. I have also seen (done on small trains) the engineer apply the automatic and just before they stop release it and apply the independent. If you know what your doing, that works well with smaller trains.James
I hope you are refering to Train Simulator when you describe that sort of train handling.
The braking method you described is actually one of the easier way to break a drawbar. Was that a new engineer you were refering to? I ask because if he had some whiskers (seniority), and was running back when there were cabooses on trains, handling a train that way, he would have put the conductor in the hospital within a week.
And you cannot "slowly" release the train brakes, unless the locomotive automatic brake valve is equipped with the 'graduated release" feature. This feature is usually only found on locomotives that might be used in passenger service (ie: CNW's F7s and E8's).
I have frequently been amazed when I see extracted (by poor train-handling) drawbars lying on the ground with the knuckle still intact. Normally, you would think that the knuckle would give out long before the drawbar. However, usually there is quite a bit of rust on the face of the drawbar where the break occurred (indicating that the drawbar had been cracked for some time prior to the actual break).
Ya sorry, I should have said passenger service. We deal with a lot with passenger trains up here and that's a good method of stopping the trains. It seems to work really well. Now as of freight railroading I just took a guess. I will be going into conductor and locomotive engineering classes soon so I will get to know all of that as soon as I am done.
Happy railroading
diningcar wrote:The BNSF is now putting an asphalt layer between the earthen subgrade and the ballast on its 2nd track TRANSCON construction.
Potter to Bound Brook, NJ, is the process of being upgraded to a dual line. I wondered why asphalt was being laid on some portions of the newly graded roadbed. Now I know.
RJ Emery near Santa Fe, NM
rjermy,
Yes, of course, existing conditions may cause a broken drawbar just as a bad wheel or a hot box may also cause an accident. Nothing is 100% safe but track subgrade design on the recent railroad construction projects not only minimizes undulation but also mitigates sags caused by poor compaction. The BNSF is now putting an asphalt layer between the earthen subgrade and the ballast on its 2nd track TRANSCON construction.
If a wheel or drawbar has an existing flaw it will likely have a seam showing rust which will be found when an accident is investigated. It has become very sophisticated out on the main line high speed RR's today.
DiningCar,
It strikes me that a drawbar could have a fatal flaw just waiting to fail from a previous bad slack control incident. Freight cars are interchanged between roads and could be on any route, any where. Then at some future time, the failure occurs with only the slightest bump. A new engineer could then be blamed for something he did not do.
How are drawbars and couplers examined for flaws or stress cracks?
beaulieu wrote:RJ, this is the kind of sag that is hard on drawbars is the Engineer fails to control the slack ... Hogback
Yes, I would call that a sag -- and then some. Hummocky and undulating terrain. A picture is worth a thousand words. Those rails and ties do not look that great either. I guess whoever built that stretch of line back when never heard of cut-and-fill.
RJ, this is the kind of sag that is hard on drawbars when the Engineer fails to control the slack
Hogback
BaltACD provides an excellent analysis of train operation and the cause of broken draw bars. Most of the severe undulation problems he mentions are found on lines whose grades were designed 100 or more years ago with the objective to reduce construction costs. Modern construction methods recognize the false economy of those designs.
A classic example is on the BNSF TRANSCON between Williams Jct. and Crookton, AZ. This original Santa Fe line was rebuilt in 1960 to expedite traffic through severe mountain conditions and employed a maximum 1% grade and one degree curves. The 44 mile relocation begins at Williams Jct. with a westward decending grade of 1% for about 31 miles. When it was necessary to climb again a 10,000 foot vertical curve was created for the transition onto a 0.88% ascending grade. The remaining distance produced no significant gradient problems so the BUFF and DRAFT forces were minimized over the entire 44 mile segment of mountain railroad. This is just one of the reasons the TRANSCON is dominating the western freight business today.
WSOR 3801 wrote:http://www.alkrug.vcn.com/rrfacts/rrfacts.htm explains it pretty good. The independent is the engine brake. Only the engines respond to this. The automatic is the train brake. All the cars and the engines respond to this.
I appreciate the reference and the elaboration. At the site you suggested, I also found a very useful explanation of railroad signaling.
BaltACD wrote:Short sags in other wise tangent, level track have been known to be real knuckle eaters as the slack adjusts itself as the train traverses the sag at speed.
Rodney and BaltACD,
Thanks for your perspectives. While appreciating it took some effort and knowledge to drive a train, I never realized just how involved the job was, especially over hilly or mountainous terrain.
Just how much of a sag would cause knuckles to wear excessively?
At Potter (ex-LV, now Conrail, in North Edison, NJ), I have often observed track in many places sag a few inches under the weight of passing locomotives and cars. I always attributed that to poor ballasting and loose or flexible wooden ties but figured if the situation were truly bad, Conrail would address it.
The action that most frequently breaks knuckles or drawbars, is unintended slack action. Where the slack within the trains (which can be up to approximately 100 feet or more in a normal 8000 to 9000 foot mainline train) run either in (toward the engines) or out (away from the engines). Then forces of run in are termed 'Buff Forces' and the run out forces are termed 'Draft Forces'.
The easiest and sometimes only way to start a train is to first 'bunch the slack'...set a minimum reduction on the train and shove the train to push all the slack possible to the 'rear', release the brakes and then start the train moving, one car at a time until the entire train is moving.....the locomotives pull first 100 tons (car 1) then 200 tons (1+2) then 300 tons (1+2+3) etc until the entire train of 10000 tons is moving. Trying to start 10000 tons all a once is a near impossibility.
With the train moving across the railroad the engineer has to control the slack of his train across the varying terrain of his territory. Continuous grades, either ascending or descending are easy for controlling slack as the entire train will be on the grade and experiencing the same forces of gravity. When the territory becomes undulating, where the train can span two or three hill crests as well as the intervening valleys, the the job of controlling slack within the train becomes paramount, as without control, the slack action can be view as being akin to 'Cracking a Whip'.....a 100 foot whip with 2000 to 8000 tons of train as the force to act against the remaining tonnage of the train. Both Buff Forces and Draft Forces can shatter knuckles. Both Buff Forces and Draft Forces can damage the drawbar/draft gear. Think of the uncontrolled 8000 tons of slack running into the 2000 ton remainder of the train at an uncontrolled speed differential of 1 to 5 MPH.....Big Buff or Draft impact. In the days of the caboose, one of the biggest cause of injuries to the Conductor and Flagman that rode the caboose was unexpected slack action, which could throw an unsecured individual right off the train in some circumstances.
Short sags in other wise tangent, level track have been known to be real knuckle eaters as the slack adjusts itself as the train traverses the sag at speed.
Hi everyone iam Rodney I am a locomotive engineer with BNSF. Let me explain on how train brakes operate, the brake pipe pressure in release position of the automtic brake valve is 90psi, when ever I make a min reduction 6-8 psi the train brakes set up from the head to the rear, if I realese the brakes the train brakes will release slowly from the head to rear (i.e. as the pressure on each car is sensing a 1psi rise they relaese (1) car at a time, if above I make an addational reduction to 10psi or below the cars will realese in a faster rate accelarated service realese as some of the air in the emergency resavioure goes in the brake pipe. I have been running for 2 years 7 monthes and am still learnig train handling.
The drawbar is the part of the coupler assembly that attaches to the car, by the draft gear. It is a stout metal casting. They can and do break, however. Most drawbars are good for 390,000 lbs of force before they snap. A SD70MAC has about 120,000 lbs tractive effort (pull). If you have 4 hooked up, that would be 480,000 pounds of pull, and the drawbar broke. http://www.alkrug.vcn.com/rrfacts/rrfacts.htm explains it pretty good.
The independent is the engine brake. Only the engines respond to this.
The automatic is the train brake. All the cars and the engines respond to this. When making a brake application, you would usually bail off the engines. This would release the engine brakes, or not let them set up at all. The engine brakes grab harder and faster than the train brakes, which could lead to problems.
Mike WSOR engineer | HO scale since 1988 | Visit our club www.WCGandyDancers.com
CMSTPP wrote:... a lot of engineers bring it down with the automatic and just before they stop slowly start releasing it to ease the train to a stop with out that slack action kicking in. I have also seen (done on small trains) the engineer apply the automatic and just before they stop release it and apply the independent. If you know what your doing, that works well with smaller trains.
Having never been inside a modern locomotive or seen how one is started, driven or stopped, please explain what is meant by the automatic and independent.
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