I read that Consolidated steam locomotives (2-8-0 wheel configuration) on D&RG narrowline tracks had only 2 of the 4 pairs of driving wheels flanged. This allowed them to better negotiate sharp curves and put less wear on the track. That makes sense to me. Which 2 axles would typically be flanged? Would there be any time that the non-flanged wheels were completely off the rail in a tight turn? Was that ever done on long standard gauge steam locomotives? Was it ever done on diesel locomotives, like the double UP units?
Thanks to Chris / CopCarSS for my avatar.
I was going to offer some info, but Google helped:
http://cs.trains.com/trn/f/111/t/4087.aspx
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...
Murphy Siding I read that Consolidated steam locomotives (2-8-0 wheel configuration) on D&RG narrowline tracks had only 2 of the 4 pairs of driving wheels flanged. This allowed them to better negotiate sharp curves and put less wear on the track. That makes sense to me. Which 2 axles would typically be flanged? Would there be any time that the non-flanged wheels were completely off the rail in a tight turn? Was that ever done on long standard gauge steam locomotives? Was it ever done on diesel locomotives, like the double UP units?
The four wheels of the outer two axles would be flanged.
Regarding a flangeless wheel shifting sideways and passing completely off of the rail:
All wheel suspension on locomotives has mechanical systems to equalize the loading on diesel power trucks or steam locomotive drivers. Loading must be equalized for power to be uniformly applied to the rails by each driven wheel.
Since the track has elevation irregularities, the wheels must be able to move up and down while maintaining uniform loading. So with this equalization, a flangeless wheel that ran off the rail head would drop down onto the ties.
If the flangeless wheel were prevented from moving up and down, it would ride up over a hump in the rail and lift the two adjacent flanged wheels off the rail and cause them to derail.
Incidentally, I can't think of any internal combustion locomotive with flangeless wheels.
Drivers without flanges were traditionally known as 'blind', and you will find many references to them if you search using that name.
We have discussed what is necessary to keep these drivers from derailing on this forum before, including 'doubling' the rail on curves to ensure adequate bearing surface. In some cases the blind tread was made very wide to keep it from dropping off.
Much of the perceived need for blind drivers was reduced by introduction of the controlled lateral-motion device. If I recall correctly, the PRR I1 2-10-0 had three sets of blind drivers before lateral motion devices were installed (on the 2nd and 4th driver pairs); the center main driver remained blind. This on a large engine with no trailing truck or tender guidance of the rear of the frame, operated routinely up to 50mph.
Found a drawing on line of a
showing the middle three pair of drivers as 'blind'.
Make that a 2-10-0 {Decapod] My mistake, shows me why the eye doctor says I need new glasses....
There is also a really good one of AT&SF # 1 (nee132) now on display at the Kansas Historical Society Museum in Topeka. I was used by AT&SF until 1961, when it was placed for display (with a Drover's Coach and Co. Office Car) with the Kansas Historical Society. The photo link below shows it in operating condition in 1961. @ http://www.rrpicturearchives.net/showPicture.aspx?id=2996203
Here is a link to the history of the #132 now displayed in the KHS Museum(Topeka) @ https://www.kshs.org/kansapedia/cool-things-locomotive/10168
samfp1943 Found a drawing on line of a 2-8-0...
That's a 2-10-0. Still illustrates the concept.
samfp1943Found a drawing on line of a 2-8-0 (Consolidation) showing the middle three pair of drivers as 'blind'. http://www.altoonaworks.info/graphics/drawing_i1s.jpg
Sam: You will recognize from simple arithmetic that 'the middle three pairs' on a 2-8-0 doesn't add up right.
Remember the PRR I1s I posted about a few hours ago? Look at the drawing name of the file you posted, count the drivers, and tell me if it looks familiar now...
About eleven years ago, my wife and I camped up-Island near a a logging camp called Woss. Until about ten years previously, the outfit had run summer excursions with their old 2-8-2. We found it parked on a short stub track near the road into the lumber yard. I had not noticed the blind drivers, but as we both walked back to the turnout, I couldn't help but notice how impossibly sharp it was at the frog angle. "No way..!" I exclaimed to my wife. I turned and said to myself, "Unless...," and we walked back the 70 or so feet to the loco. Sure enough...
Very good shot and as they say a picture is worth a thousand words. I had read about blind drivers but never seen them. Thanks.
I am familiar with blind drivers, and have seen the blind tread made extra wide to avoid dropping off the rail, but never heard of adding extra rails on curves to pick up a blind driver that drifts off of the normal stock rail. Was this done by just adding a second rail of the same size as the main running rail; and adding it alongside the main running rail with the bases of the two rails touching? I guess the bases would have to be spaced apart to accommodate the spikes. I assume that the extra rails were added inside of the outer rail of the curve, and outside of the inner rail of the curve. Can anyone provide a picture or drawing of this?
EuclidWas this done by just adding a second rail of the same size as the main running rail; and adding it alongside the main running rail with the bases of the two rails touching?
This reference from 1889
selector About eleven years ago, my wife and I camped up-Island near a a logging camp called Woss. Until about ten years previously, the outfit had run summer excursions with their old 2-8-2. We found it parked on a short stub track near the road into the lumber yard. I had not noticed the blind drivers, but as we both walked back to the turnout, I couldn't help but notice how impossibly sharp it was at the frog angle. "No way..!" I exclaimed to my wife. I turned and said to myself, "Unless...," and we walked back the 70 or so feet to the loco. Sure enough...
Murphy Sidingselector About eleven years ago, my wife and I camped up-Island near a a logging camp called Woss. Until about ten years previously, the outfit had run summer excursions with their old 2-8-2. We found it parked on a short stub track near the road into the lumber yard. I had not noticed the blind drivers, but as we both walked back to the turnout, I couldn't help but notice how impossibly sharp it was at the frog angle. "No way..!" I exclaimed to my wife. I turned and said to myself, "Unless...," and we walked back the 70 or so feet to the loco. Sure enough... Why are the end axles the ones with the flange and not the center ones? Wouldn't you want the flanged ones closer together verses farther?Is that the sanding tube snaking around the right hand side of the far right wheel?
Why are the end axles the ones with the flange and not the center ones? Wouldn't you want the flanged ones closer together verses farther?Is that the sanding tube snaking around the right hand side of the far right wheel?
The flanges are to the outside because of the torque that would be applied by the inner drivers if the flanges were on them. Rip the rails right off the ties! On the outside drivers they are leverage to keep the engine from turning sideways! The engine could twist off the track easily if the flanges were on the inner drivers.
Yes, that looks like a sand pipe.
Semper Vaporo
Pkgs.
Murphy Siding selector About eleven years ago, my wife and I camped up-Island near a a logging camp called Woss. Until about ten years previously, the outfit had run summer excursions with their old 2-8-2. We found it parked on a short stub track near the road into the lumber yard. I had not noticed the blind drivers, but as we both walked back to the turnout, I couldn't help but notice how impossibly sharp it was at the frog angle. "No way..!" I exclaimed to my wife. I turned and said to myself, "Unless...," and we walked back the 70 or so feet to the loco. Sure enough... Why are the end axles the ones with the flange and not the center ones? Wouldn't you want the flanged ones closer together verses farther?Is that the sanding tube snaking around the right hand side of the far right wheel?
The axles that have the flanges determine the position of the locomotive on the curve. If the inner axles had the flanges, the locomotive would be less stable in position and could oscillate from side to side.
The flangeless driving wheels often have wider tyres than the flanged wheels and this appears to be the case in the photo. This makes them less likely to derail. They are still conical in shape which causes them to move to the centre on tangent track. while allowing them to move across the rail head in curves.
And there does appear to be a rear sand pipe.
(edit: posted before the previous post appeared...)
Peter
M636C And there does appear to be a rear sand pipe. Peter
Murphy Siding M636C And there does appear to be a rear sand pipe. Peter How does a rear sand pipe help adhesion? Wouldn't you want that in front of the wheels?
How does a rear sand pipe help adhesion? Wouldn't you want that in front of the wheels?
Engines operate in both directions.
Never too old to have a happy childhood!
BaltACD Murphy Siding M636C And there does appear to be a rear sand pipe. Peter How does a rear sand pipe help adhesion? Wouldn't you want that in front of the wheels? Engines operate in both directions.
Yes, there should be a pipe in front of the front driver. A few engines had pipes in front and behind each wheel or just in front of the front couple of drivers and behind the rear couple of drivers.
I've looked up the data for the Deutsche Reichsbahn (pre-1945 German State railways) Class 50 decapods. They were similar in dimensions to the PRR decapod shown in a previous post. Built to the tune of 3141 examples, they were as ubiquitious postwar as Ford Model T's in the 1920s. Anyway, they had a distance between driver centers of 65 inches, a wheelbase of just over 30 feet, and could negotiate curves with a minimum radius of 460 feet. The first and last driver axles had 25mm (one inch) of sideplay, and the center axle (the driving axle) had flanges that were 15mm (0.60 in) thinner than those on the other axles. This seems to have been the typical arrangement of German mainline locos of the period (late 1930s), probably because the minimum radius wasn't too tight. Goelsdorf-inspired designs usually had two axles without sideplay and the rest with different amounts depending on their position in the frame. I don't think blind drivers were used much, German designers rather used mechanically more complicated arrangements like Luttermoeller axles - the end axles were driven not by side rods, but by cogwheels centrally mounted on the axles from the neighbouring axles, which allowed them more sideplay and some degree of radial steering.
A close look at those blind drivers, as I stooped and did when I realized what I was looking at at the time, shows the outer rim to be beveled at about four/five degrees. That would be to ensure a cam effect to help the rim edge to meet the rail head during times when the blind tire tread left the rail-proper on curves where the blind wheels went toward the center of the curve...as looking down the radius...and then returning to purchase and supporting the locomotive as the curve straightened once again.
selector A close look at those blind drivers, as I stooped and did when I realized what I was looking at at the time, shows the outer rim to be beveled at about four/five degrees. That would be to ensure a cam effect to help the rim edge to meet the rail head during times when the blind tire tread left the rail-proper on curves where the blind wheels went toward the center of the curve...as looking down the radius...and then returning to purchase and supporting the locomotive as the curve straightened once again.
I always thought that that "dished out" profile of the blind driver was wear, and that the unworn profile was a perfect cylinder. But after this discussion, I am not sure about the blind profile. Also, this discussion is the first I have ever heard of secondary rails that pick up the load of blind drivers that shift off of their running rail when traversing curves. I have never seen a reference to, or image of such a function until this thread.
I have looked at this reference posted by RME: This reference from 1889
However, I have not read it comprehensively enough to absorb it. I would almost have to transcribe it first, and then sort it out to find the meaning. It is extremely detailed, so I would have to fit the pieces together to find the larger contexts of meaning.
In any case, it shows the dished out blind driver profile that you refer to, and how it can strike the "blind driver guard rail."
I am fully aware of "guardrails," which confine and guide a derailed wheel running on the ties in order to keep it running true to the line of track; and also the guardrails on switches and crossings to prevent the flanges from picking the frogs. But a secondary rail to pick up the loading of a blind driver would be an entirely different purpose than the traditional guardrails as I mention above.
As to the purpose of guardrails at the frogs of switches and crossings; these guardrails will only bear on the backs of the wheel flanges when they are needed. This is unlike the guardrails that guide derailed wheels, which bear on a broader area of the back of the wheel. The point is that a derailed blind driver will be guided by the wheel guiding guardrail, but it will not be guided by a switch or crossing frog guardrail. Those frog guardrails only guide the flange extension, and the blind drivers have no flanges.
Therefore, maybe the article linked above is addressing the lack of frog guardrail effect with the passage of blind drivers. The illustrations show the effect of a dished out blind driver tread acting as a flange striking the guardrail. It that were the purpose of the dished out profile, then it would not be caused by wear. But then, the text does refer to worn blind drivers. So I look forward to a clear explanation of all of this.
As I mentioned a few posts up, in the case of a secondary rail to pick up the loading of blind drivers, one such secondary rail would be required for each of the two stock running rails.
I thought only model train engines had flangeles drive wheels.
Modeling the "Fargo Area Rapid Transit" in O scale 3 rail.
I am not convinced that railroads ever used secondary rails at curves to pick up blind drivers as they shifted sideways off of the stock rails. I would have to see either a photograph showing such secondary rails or a clear reference describing them.
I am not sure what these rails would be called if they ever existed. I would not call them guardrails because that term is used for rails that come into use as a backup feature during a derailment or tendency of flanges to pick frogs. Rails for blind drivers would not be for such contingencies, but rather, would function routinely with every passage of the blind drivers. So I would call them Blind Driver Secondary Rails. Unlike guardrails, these secondary rails would be shiny just like the stock running rails.
I do find references to blind drivers interfering with the stock rail at switch points, causing the stock rail to tip over; and interfering with guard rails at switch and crossing frogs. But I find nothing about secondary rails to act as running rails for blind drivers on curves.
Here is a discussion about blind drivers from Narrow Gauge Discussion Forum. I find the following comment to be particularly interesting. It too talks about the risk of worn blind drivers tipping over the stock rail when making a trailing move through the switch points off of the turnout portion of the switch.
http://ngdiscussion.net/phorum/read.php?1,19929,20031#msg-20031
“Linn W. Moedinger
May 01, 2002 04:28AM
It has been my observation that blind drivers were applied in many different ways. Sometimes the back-to-back is set at the normal maximum of 53 3/8" (sorry about the standard gauge numbers) and sometimes the tires are set narrower. 53" is the minimum back-to-back allowed and that has been exceeded with blind drivers. The tread is usually flat with a taper on either side.
The two areas that can cause problems with blind drivers (besides retarders and self-guarding frogs) are the switch points and guard rails. If a switch is constructed properly the switch point rails themselves ride on risers that elevate the head of the rail above the stock rail by 1/4". This is to ensure that as the wheel riding on the point in a trailing direction approaches the stock rail, it does not catch the stock rail with the outside edge of the wheel. When this occurs the stock rail can roll over. The taper on blind drivers helps to minimize this possibility. The combination of hollow tread and insufficient rise in point rails can be pretty hard on switches to say the least. Guard rails are usually a bit higher than the stock rail. When a tire is set in below the minimum back to back this can cause undo pressure on the guard rail. With blind drivers set in below the minimum there is usually no problem because the taper allows the tire to ride over the guard rail. With many relay turnouts in service it is not uncommon to see stock rails with 1/4" head wear mated to guard rails that, even though they are the same rail type, they would end up being at least 1/4" higher than the stock rail. With this condition a hollow but legal blind driver set below minimum back-to-back would catch the guard rail.
Excessive lateral motion in any of the driving axles can cause blind drivers to drop off the rail on tight curves.
For the most part blind drivers do not have to be set narrower than minimum. The center of 85 lb. P.S. (2 1/2" head width) rail set to gauge is 59". The center of a 6" blind driver tire set at minimum back-to-back of 53" is 59". This allows equal overhang on the inside and outside of the rail and is the reason for the 1/2" greater width of a blind driver tire than a standard flanged tire. Self-guarding frogs must be run through carefully with blind drivers because of the additional outside width of the tires.
It has been my experience that the minimum standards set up by the FRA are just that. Staying on the track can be the exception rather than the rule if you are at the minimums and just legal with track gauge, switch standards, tread worn hollow, thin, deep, or vertical flange, and maximum lateral.”
Here is an earlier discussion of blind drivers from this forum:
http://cs.trains.com/trn/f/741/t/162184.aspx
EuclidI would have to see either a photograph showing such secondary rails or a clear reference describing them.
I'm quite certain I've seen such an image. Finding it again may be a challenge.
MC might have a source.
The other thread pointed out that such long wheelbase locomotives as a 2-10-2 would likely have spent most of their time on lines with gentle curves (ie, mainlines). The need for a protective rail would thus have been limited to such locations as those locomotive might occasionally visit (ie, shops).
Wear on such a rail might cover only a small part of the railhead. If that section of track saw only occasional use by blind-drivered locomotives, it might show almost no wear at all...
tree68I'm quite certain I've seen such an image. Finding it again may be a challenge.
I don't know if the Maryland and Pennsylvania had blind drivers on their engines, but they had guard rails on their many sharp curves. Still existing on the stretch the Ma & Pa historical society runs speeders on.
The opinions expressed here represent my own and not those of my employer, any other railroad, company, or person.
zugmannI don't know if the Maryland and Pennsylvania had blind drivers on their engines, but they had guard rails on their many sharp curves. Still existing on the stretch the Ma & Pa historical society runs speeders on.
Such protection rails would have been toward the center of the radius of the curve - thus on the field side of the inside rail on a curve, and on the guage side of the outside rail.
The guard rails in the video look to be there to keep equipment from wandering too far afield, either if the inside wheel tries to slip off the rail, or the outside wheel tries to climb the rail.
Yes, the Ma & Pa extra rail is a guardrail. I understand that part of their purpose is to reduce flange wear on the outside rail by preventing outward shift of the wheelset by holding back the back of the flange on the wheel running on the inside rail of the curve. At the same time, it would prevent the outside flange from climbing the outer rail either from centrifugal force or a sharp flange.
Being that this guardrail is intended to catch the side-shifing flange, it is as high as the stock rail. Typically, for guard rails that are intened to guide derailed wheels, the guard rail is smaller, so it is not as tall as the stock rail.
Rail intended to pick up the load from blind drivers shifting off of the main stock rail would have to be two rails; one on the inside of stock rail that is outside of the curve; and one on the outside of the stock rail that is inside of the curve.
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