# EBT minimum diamiter curve



## aceinspp (Jan 2, 2008)

What is the min that one can operate this loco on? Any issues with the two center blind drivers? Later RJD


----------



## Tom Bowdler (Jan 3, 2008)

I have been successful running mine on my portable track, 6' radius (12' dia) outer loop, 5' radius (10' dia) inner loop. 
Tom


----------



## Larry Green (Jan 2, 2008)

While I run mine on 10' radius, there is a curved switch with an 8' inner track radius that the engine finds tight. No problems with #6 switches. 

Larry


----------



## Larry Green (Jan 2, 2008)

Just remembered something related--there is a picture somewhere of one of the EBT mikes on the curved part of the wye at the picnic grove. The two blind drivers look to be almost completely off the rail head. 

Kevin--you out there? Do you know this photo? 

Larry


----------



## jfrank (Jan 2, 2008)

I use a 6' minimum radius and it operates ok on that. It's a big engine so I would not go much tighter than that.


----------



## East Broad Top (Dec 29, 2007)

Larry, this the one? This was taken at Rockhill Furnace. 

This is why blind drivers are wider than flanged drivers. On the EBT, it's 5.5" total width (including flange) for the flanged driver, 6.5" width for the blind drivers. (The standard gauge PRR used 6" and 8" respectively.) For some strange reason, model manufacturers generally do not copy this. 

I've run mine on my 5' radius curve, and while it does bog down a bit, so do my sparkies, so I think there's something on the curve more than the loco's ability to go around it that's in play. Still, a loco that large looks odd going around a curve that tight. Operationally, the drivers do stay on top of the rails. 

Later, 

K


----------



## Greg Elmassian (Jan 3, 2008)

You are right Kevin, seems they don't want to spend money or really understand how this stuff works. 

I've seen derailments when blind drivers go off the rail and cause trouble climbing back on. 

Simple concept that seems to have not made it from prototype to model. 

Greg


----------



## aceinspp (Jan 2, 2008)

I run mine on mostly 10 ft diamiter and have problems with derailements. I find it hard to believe one runs on 5 ft radius and not see the blind drivers slip to the in side of the rail. What I'm looking for is how much presure is actually on the blind drivers and are the front and rear pony trucks part of the equation to help support the loco. Are your drivers actually touching the rail head. I also have several wide radius turnouts on the RR and the loco will also derail on them. Later RJD


----------



## Totalwrecker (Feb 26, 2009)

Undersized flangeless drivers is the easiest toy train solution, we don't have equalized suspensions. 
Our 10'D curves are not all that 'big' compared to HO. I tend to use HO as that's where I grew from toys to models. 
10'D = 60" R, therefore 1/2 scale down to a rough O scale is: 30"r and then HO comes in at 15"r, smaller than was included in starter sets. No wonder our locos like to cut corners! 

John


----------



## Greg Elmassian (Jan 3, 2008)

John, in this situation, are you saying that although the drivers are sprung, they are not equalized and that makes it more difficult tracking? (which makes sense to me). 

Greg


----------



## Dave Meashey (Jan 2, 2008)

To add to what John mentioned, I remember that my American Flyers only had four drive wheels with flanges - it didn't matter what the wheel arrangement was. The rigid cast frame kept the blind drivers from dropping whenever they left the rail. That does not work too well when models have sprung axles. I think Hornby OO English locomotives solved the problem with a rigid frame and blind drivers that were 1 or 2 mm smaller in diameter than the flanged drivers. (It was visually jarring to me when I tried to watch the valve gear motion on my nicer Hornby steam locomotives.)

On the W,K&S tourist railroad, the little Porter 0-6-0 saddle tanker even had blind drivers on the center axle, and yes, they were "steamroller width" wheels.

I am guessing that most models already have wider tread flanged drivers, due to our sharper curves, so manufacturers tend to keep the blind drivers at the same tread width to save cost. With sprung axles it would probably be better to widen the blind drivers anyway.

Hey Kevin;

The rail under that EBT Mike is badly in need of some rail head profiling. Too bad nobody has a rail grinding service for 3 foot gauge. The extra metal hanging off the outside of the rail head made me wince a bit, but I don't suppose anything moves fast enough over those rails to cause a real problem. The W,K&S has some old wrought iron rail in Twin County Cut. (Don't know how true it was, but one of the "old timers" told me that the wrought iron rail was laid around 1890.) Hoggers were warned to pay special attention to the rail there - and to go easy on the throttle.

Fun stuff, David Meashey


----------



## East Broad Top (Dec 29, 2007)

Okay, I just checked mine on my 5' radius. I _can_ play with the lateral slop in the drivers to where the outside wheel on the middle (blind) drivers comes off the railhead on the outside rail, but the inside wheel is still in contact on the inside rail. (Condition: left-hand curve; flanged drivers pushed to the right, blind drivers pushed to the left for maximum offset in the opposite direction of the curve.) There's not enough lateral play on mine to where both wheels on the axle drop off the railhead. It appears--on mine at least--that the wheel still sitting on the inside rail is enough to keep the outside wheel from dropping below the railhead. I can push down on the loco, compressing the springs, and get it to do so, but under its own weight, it doesn't appear to be an issue. 

The weight of the locomotive itself may be an issue, though. I'm using AMS code 250 track which is very tight in the ties. I've run it on another railroad where the rails were loose on the ties (old wood ties with loose spikes) and it spread the rails just due to the weight. Lighter locos had no troubles. If you're running on Aristo or similar flex track where the rail has a bit more "play" in the ties, it may be that the weight of the loco could be broadening the gauge on you. Can't say for certain, but something to look into. 

RJ, when you say "wide radius" switches, what are referring to? Number 6 switches don't pose any problems for me, but I've not run it over the Aristo's 5' radius switches that are on my indoor shelf railroad. (I have to note that I've got lots of locos that derail over Aristo's 5' radius switches, though, so I'd have to say if my mike did have issues on those switches, it wouldn't likely be related to the locomotive.) 

Later, 

K


----------



## jfrank (Jan 2, 2008)

Posted By aceinspp on 04 Apr 2013 10:25 AM 
I run mine on mostly 10 ft diamiter and have problems with derailements. I find it hard to believe one runs on 5 ft radius and not see the blind drivers slip to the in side of the rail. What I'm looking for is how much presure is actually on the blind drivers and are the front and rear pony trucks part of the equation to help support the loco. Are your drivers actually touching the rail head. I also have several wide radius turnouts on the RR and the loco will also derail on them. Later RJD 

I think you have some other problem. I operate everything from a Ruby to a K36 on 6' radius(12' diameter) and I have never had a problem with blind drivers causing a derailment and I have a large railroad with lots of curves and switches. I use primarily #6 Llagas Creek switches, but I have a few #5's and some Pecos. I have steamups with people bringing all kinds of engines and all makes and sizes(except the large Aster's and Accucraft's that take 10' radius)


----------



## weaverc (Jan 2, 2008)

John has a good idea. Try checking the gauge of the wheels on each of the axles including the blind drivers. Sometimes a set screw comes loose or it was not right to start with.


----------



## Pete Thornton (Jan 2, 2008)

This is why blind drivers are wider than flanged drivers 

I can comment that sometimes they get modelled correctly. 










This is the RY Models EBT Mikado.

Interestingly, I have had no issues with tracking on my Accucraft #12. It seems to take any kind of track problems in its stride. However, the RYM #15 (pictured here) will regularly hit the ballast - I haven't quite decided whether it is the front truck that is not allowing enough movement or whether the front axle isn't flexible enough.


----------



## aceinspp (Jan 2, 2008)

I do not think that the blind drivers on the Accucraft EBT are any wider than the rest of the wheel sets. John you mention other problems, If you read my reply I said 10 ft not larger as you use so there is a difference in curvature that may cause an issue. After futher observations of my loco, checking the front and rear pony trucks do make a difference when changing to different spring rates. i thought that this may have been an issue. However after reinstalling the original springs it appears that it helps maintain the center blind drivers to be clear of the rail and not set directly on the rail. I was able to slip a receipt card under the two bind drivers with out problems. So this may have been part of my problem when I removed the orginal springs when I had issues. 

Keven AC turnouts designated as wide Radius as you should know are roughly 10 ft diameter on the turn out side. Yes these turn outs are not the greatest for any type of loco weather LS or sparky.

David: one need not worry about the rail wear on the field side of the rail as you are not operating there. The condition is known as flowed rail. The flow is due to distortion of the rail metal under repeated loads. This does not damage the rail Normally this type of condition occurs in curved track but can also show up on tangent track. RR do not grind the field side of rails. Normally when rail gets to this point the rail is removed as requested by the friendly FRA inspector. Later RJD


----------



## East Broad Top (Dec 29, 2007)

RJ, figured that's what you meant by "wide radius," but figured it prudent to ask.  

Pete, I'm not surprised Rich got it "right." Bachmann has done the same thing on their new C-19, which I found refreshing. As for your #15 hitting the ballast, obviously it's trying to dirty itself up properly. Get some weathering on that loco, already!  

Later, 

K


----------



## Pete Thornton (Jan 2, 2008)

I do not think that the blind drivers on the Accucraft EBT are any wider than the rest of the wheel sets 
No, I don't either. But all my wheels sit on the rails - I'll try and find a photo - so I don't know why you can slip a card under them. Aha - here's #12 with all four wheels visible. 










Get some weathering on that loco, already!  

As you are perfectly aware, it got very dirty a while ago.







Interesting difference between the two sets of blind drivers.


----------



## aceinspp (Jan 2, 2008)

The best way to observe the drivers on the rail is to put it up on a shelf so you can get a really good look at the drivers. One should not assume that they are touching totally without doing my test. Look at the spring tension on the two pony trucks also. Later RJD


----------



## Pete Thornton (Jan 2, 2008)

Posted By aceinspp on 05 Apr 2013 10:45 AM 
The best way to observe the drivers on the rail is to put it up on a shelf so you can get a really good look at the drivers. One should not assume that they are touching totally without doing my test. Look at the spring tension on the two pony trucks also. Later RJD 

I am sure they are touching on my loco. And note the EBT Mikado took the drawbar pull trophy at last year's Diamondhead meet - unlikely to manage that without all eight wheels doing some work. 
My loco spends most of its life on the shelf - unfortunately.


----------



## Greg Elmassian (Jan 3, 2008)

Remember (on smooth, flat track) the tractive effort is the weight on the drivers and the coefficient of friction... more or less drivers does not matter. 

Basic law of physics. 

Tractive effort on that nice piece of track should be same if only 2 axles were touching (outer ones to keep weight on drivers the same) 

So, good pulling on our MODELS on GOOD track does not prove that the center 2 drivers are touching. (notice the caveats in caps?) 

Greg


----------



## Pete Thornton (Jan 2, 2008)

the tractive effort is the weight on the drivers and the coefficient of friction... more or less drivers does not matter. 
I had a feeling someone would make that comment (no surprise who took the opportunity.) 

But I would point out that more drivers in contact with the rail reduces the need for the coefficient of friction to be high. My Mike will start a very heavy train on a hill - try that with only 4 drivers touching the rails.


----------



## aceinspp (Jan 2, 2008)

You know you have not even bothered to check to see if all the wheels are really touching the rail head. Here again no one really wants to do the check just want to talk about how good pulling power of there loco is. Folks really need to do some good investigating on what goes on with locos such as Greg ,Ted and I do. BTW I'm going to let Greg tell you about the laws of physics. 

So Pete please walk over to your mantel and see if you can slip a piece of paper under the drivers on either sides. 
Later RJD


----------



## East Broad Top (Dec 29, 2007)

RJ, if the blind drivers are held above the rails on yours when it's sitting on the rails under its own weight, then something's weird with the springs on your loco. When I set mine on the rails, the weight of the loco compresses all of the springs on all of the drivers. I've seen two others running in the flesh, and they all seem to exhibit identical properties. 



This was shot at the Colo. RR museum's track before we re-laid it. Lots of subtle ups and downs, especially in the yard areas. I've spent plenty of time watching this loco just crawl over that uneven track as if it were smooth as glass. 

From what you've written, I wonder if the springs on your pilot and trailing truck are too stiff, and bearing too much weight of the locomotive. At least, that's the only thing I can think of--given properly functioning springs on the main drivers--that would keep them from compressing under the full weight of the loco and not sitting on the rails. The drivers aren't supposed to sit above the rails, so if the pilot/trailing truck springs are--literally--jacking your drivers up off the rails, then you're not getting the pulling power or tracking you should from the locomotive. 

(mod hat on) 

Let's everybody remember to keep the tone of this discussion polite and constructive, please. Not singling anyone out, just a friendly reminder that we're all just trying to help someone fix a problem with a locomotive. 

Later, 

K


----------



## East Broad Top (Dec 29, 2007)

I got home and checked the drivers on mine sitting on the rails on my shelf. With no water in the boiler (its current state), the engineer's side wheel on the #2 axle sits _just_ above the railhead. (I can see light shining under the tread, though when I slide a piece of paper in there, it does meet some resistance, so the gap is thinner than the paper.) All other wheels are in contact with the railhead. Putting just a little bit of weight on the loco (akin to filling the boiler) puts all wheels in contact with the railhead. The wear and dirt/oil that is collected on all the wheel treads would indicate that during operation, all wheels are in contact with the rails. 

When I sit the loco on a table (not on rails, but resting on the flanges), the blind drivers do not touch the table, instead sit about 1mm or so above the surface. Based on that, I'd presume that if the loco was to go around a curve tight enough to where the wheels would come off the railhead, the springing in the loco is such that they would not drop more than a few thousandths below the railhead, thus would easily ride back up as the rail came back underneath the tread. 

Later, 

K


----------



## Tom Bowdler (Jan 3, 2008)

Amazing video, 
I have watched it many times, one of few that has the loco moving at a prototype start up speed. This time I tried to see if the blind drivers went wider than the rail but didn't spot any instances. I am not home so can't check driver position relative to the surface and though I took physics it was a long time ago. I submit that a video of RJD's loco running through the troublesome areas at slow speed would give a world of information to help solve the problem. 
My 5' and 6' r on the portable track has carefully constructed AMS and Sunset Valley dual gauge track on a flat surface with no switches and one of Accucraft's F4/F5's ran on it though only backwards. Carl Berg's classic 32mm Commordore Vanderbilt converted to steam runs like the proverbial bat around the 6' radius loop. Often the portable is set up indoors and those two factors (track and environment) eliminate some variables. 
Or maybe I'm just lucky to have a wonderful EBT #12 and RJD doesn't. When I get home Sunday I'll put it on a table and check driver height then I'll push it around the 5'r on the portable and see where the blind drivers sit laterally on the rails. 
Have fun, 
Tom


----------



## aceinspp (Jan 2, 2008)

My observations so far operating at a slow speed prior to reinstalling the pony truck springs show the center drivers dropping inside the rail head and not able to climb back out thus causing the loco to derail in an 8ft diameter curve. (Here again Kevin you are guessing or assuming.) This is when all wheels touched the rail head. Now reinstall the original springs and we have slight daylight between center drivers and rail head thus letting the loco now operate without derailing. Yes adding water to boiler does lower it but sill no contact on rail head. I have also check the springs on each axle for any binds or any other indication to prevent the drivers from sitting on the rails. 

Do we actually know if Accucraft designed this loco to either have all drivers riding the rail or not. Is this the only run of this loco? Seems to be a lot of verbals on this loco. Later RJD


----------



## Pete Thornton (Jan 2, 2008)

You know you have not even bothered to check to see if all the wheels are really touching the rail head 
RJD, 
I'm sorry, but I am in Florida and the loco is sitting on my shelf in Maryland. I have to rely on memory and the photos - most of which I have posted. 

I'll be back to MD next week and running the loco at Cabin Fever (I hope.) I will definitely do the paper test the minute I get home! 

Here's a still from Kevin's video (above. Awesome running shots.  Sure looks like the wheels are on the rails.


----------



## East Broad Top (Dec 29, 2007)

RJ, of course I'm guessing. I don't run my loco on 4' radius curves, nor have I seen your loco running to be able to try to figure out what's happening there. I can tell you how my loco performs in given situations and simulations, and I create hypotheses based on those results. I know my locomotive, factory fresh, fully loaded with fuel and water, runs over 5' radius curves without derailing, and with all the drivers in contact with the rails. Is that how it's "designed" to work? Heck if I know. It works, that's all I care about. 

My suggestion would be to not worry about how Accucraft "designed" the loco, and find the solution that works for you. History (as illustrated by Dave Hottman, Charles and Ryan Bednarik, and countless others) has demonstrated Accucraft's designs aren't always ideal for all situations. Each loco is unique, and everyone's track is different. Do what ya gotta do to get the train around the track, and smile once it does so. 

Later, 

K


----------



## aceinspp (Jan 2, 2008)

Well if your guessing why bother, your no help. Pete I will be waiting on what your findings are. Should be interesting. At least someone will be taking the time to help research the issue. Later RJD


----------



## Pete Thornton (Jan 2, 2008)

At least someone will be taking the time to help research the issue. 
Ahem. I think Kevin already did a little research for you. Tom and I would love to rush to help, but neither of us are near our locos. Larry - how's #13 ? I have pics but they don't prove the weels touch the rails!


----------



## Larry Green (Jan 2, 2008)

Pete, 

I'm staying out of this one now, getting too split-hair technical for me. 

My mike pulled 15 cars right out of the box, and has pulled more on other occasions; that's good enough for me. 

Larry PS--sending you a PM later re: Dreyfus Hudson.


----------



## aceinspp (Jan 2, 2008)

It appears that I have exhausted the knowledge on the this forum so I will consider going elsewhere to obtain the info that I seek. Later RJD


----------



## Tom Bowdler (Jan 3, 2008)

Well, I promised, 
After arriving home this afternoon towing our camper in a stiff wind which knocked down a bunch of tree branches, tore up some of the dibond covering my railway frame twisting the track all to heck, then going down into my workshop to check EBT #12 but discovering a burst pipe in the wall above which flooded the floor and wet all the tools, materials and projects on the bench....I'm trying to rise above it all but my hoped for trip to Cabin Fever next weekend is now in jeopardy. :-( 
I got out a section of my portable track, set it up and put #12 first on the outer 6' radius curve then the inner 5' radius loop. I could slide a piece of paper under the front flangeless wheels but not the back set which sit firmly on the rail. Even when moving the axles laterally to their limits the flangeless drivers are always somewhat over the rails so with mine at least they would always have contact and not drop along side the rail on 5' and 6' radius and certainly not on my 10' r outdoor track. (which I didn't try) As near as I can tell the front and rear trucks track well and stay on the rails, whether due to the truck springs or their weight I have no idea. 
Without seeing your loco in action and checking it personally I am most suspicious of the track. I have seen Kevin's #12 run via video and Pete's, Larry's and mine in person and they are as advertised. I also know each of them personally (Kevin used to live near here) and they are straight forward, caring individuals who genuinely wish your loco was as good as theirs. My advice would be to get a local expert to look at your loco on a flat raised track or go to a big meet such as Cabin Fever where several folks could help analyze your difficulty. When having a problem I find it valuable to run the loco as slowly as possible through trouble areas to better see what is occuring. It also helps to not get upset and keep a positive attitude. 
Good luck, 
Tom


----------



## Tom Bowdler (Jan 3, 2008)

Evidently we were both typing at the same time, 
Where ever you go for help I for one would like to know what you find out and that your loco is running well. There are significant limitations to long distance diagnosis which I also run into at times professionally. As much as I/we would like to help it isn't always possible. 
Best wishes, 
Tom


----------



## Larry Green (Jan 2, 2008)

Hi Tom, after what you found upon returning home, I really admire your ability to "not get upset and keep a positive attitude". If it had been me, I would have most likely ignored anything to do with #12. 

Regards, 

Larry


----------



## East Broad Top (Dec 29, 2007)

RJ, I really don't know what other data I can give you about my #12. I've checked mine on my 5' radius curves, set it flat on a table to see what would happen with mine being supported solely by the end drivers, performed your "paper test" per your request and told you what my results were (nearly identical to Tom's). That's about all I can do... I can't tell you anything about your loco because I've not seen your loco. The best I can do is tell you how mine behaves and you can compare that to yours. Sorry you feel that's "no help," but it's the best I can offer without seeing your loco in person. (I _am_ willing to travel, mind you, if you're willing to pick up the air fare.  ) 

One more thing to check on your loco is how easy it is to rock side to side. While it takes a fair amount of downward pressure on mine to get springs on both sides to compress, it takes very little effort to rock the loco to one side. I set my loco on a section of LGB 1600 curve (the closest thing I have to 4' radius, though tighter), and just sitting on the track, the blind drivers are even with the railhead, but right on the edge of the railhead where it can easily drop off. When I press down directly from above, it takes a great deal of force to get the wheels to drop below the railhead. However, when I apply pressure to the _side_ of the locomotive (a la centripetal force), it takes very little force to rock the loco to the side, and the blind drivers easily dip below the railhead about half the width of the tire. 

I'd be willing to bet that might be what's happening with yours. (yes, it's another "guess.") If you're hitting those curves at anything more than just a crawl, the centripetal force on the loco is probably having a very easy go at rocking it to the outside. How to fix that is a trickier issue. Stiffer springs on the #1 and #4 axles might help, but then you run into other tracking problems when it comes to adapting to twisting track. I'd probably look to install some kind of stabilizer bar similar to what's on the front end of most autos. You'd have to install it into the bearing blocks themselves and anchor it to the frame of the loco somehow. 

I wish you the best of luck with your #12. I look forward to someday seeing video of it running your rails as gracefully as mine and others I've seen run do. It really is a magnificent locomotive. 

Later, 

K


----------



## Pete Thornton (Jan 2, 2008)

I will consider going elsewhere 
RJD, 
I hope they treat you as politely as we do, considering the irritation you are showing. You should thank your lucky stars there is an internet and MLS, but we're not magicians and, quite frankly, I don't know why we bother trying to help sometimes. 

It's a bit like the Moderators job - a thankless task. [And no, this isn't a personal attack - it's a polite response to your negativism.]


----------



## Greg Elmassian (Jan 3, 2008)

"no surprise who"? Want to talk about politeness? "let he who is without sin throw the first stone"...

Anyway you are still wrong Pete. Does the rail and the drivers have tiny people inside them changing the coefficient of friction lower since more drivers are in contact? 

No, of course not, the coefficient of friction between the rails and the drivers remains constant, the materials do not change to suit your driver arrangement.(this is what you are saying)

The tractive effort is driven directly by the total weight on the drivers, 4 or 8 does not matter. 

There are no special laws of physics for steam locos.

Total "normal" force and coefficient of friction that simple. I gave caveats before for drivers not in contact with the rail. 

Greg 
Posted By Pete Thornton on 05 Apr 2013 02:22 PM 
the tractive effort is the weight on the drivers and the coefficient of friction... more or less drivers does not matter. 
I had a feeling someone would make that comment (*no surprise who took the opportunity*.) 

But I would point out that more drivers in contact with the rail reduces the need for the coefficient of friction to be high. My Mike will start a very heavy train on a hill - try that with only 4 drivers touching the rails.


----------



## jfrank (Jan 2, 2008)

Posted By aceinspp on 07 Apr 2013 05:18 PM 
It appears that I have exhausted the knowledge on the this forum so I will consider going elsewhere to obtain the info that I seek. Later RJD 
Some people just don't want to admit that THEY may be the problem. You messed with your EBT and now you want to blame anything and everything else. I have had #12 running over here around 6' and 5' radius curves with no problem whatsoever as well as many other large Accucraft NG locomotives. I think your problem is 'operator error'. Good luck wherever you are going now. lol.


----------



## SD90WLMT (Feb 16, 2010)

I really need to point out one concept everyone has missed so far and should not be assumed to be OK - correct -o mon-do.. per sa.... 

And to be fair and clear here, I re-read this entire thread and this thought was never even mentioned.... 

the loco is not the only possible problem here... 

What does it ride on..? Rails,, 

Ok ready now, someone please check the gauge of the track in question on the home road fer this loco, that has an abnormal problem that no one has gotten to the bottom of trying as hard as y'all can using the typed word, have never seen the issue first hand... 

It is not just the loco in play here - no pun intended boys - , put rather the ''interaction'' of the wheels and the rail... who says where the problem is.....? 

My conclusion is missed diagnosis at this point... 

Everything needs to be considered to solve a problem... 

Thanks, - Dirk


----------



## Pete Thornton (Jan 2, 2008)

No, of course not, the coefficient of friction between the rails and the drivers remains constant, the materials do not change to suit your driver arrangement.(this is what you are saying) 
Greg, 
You still missed the point. Reading my new "20th Century" book, the Hudson's weren't considered wonderful because they were 'slippery' - unlike the 8-coupled locos that had more overall grip. 

If the CoF is high, then as you point out, 4 wheels will have as much grip as 6 or 8. But if the CoF is somewhere marginal, then the number of wheels attempting not to slip is important, as is the weight on the wheels. 

The EBT Mike is a heavy loco (30 lbs or so) and I have never seen my loco slip. But if you have bad springing and all the wheels aren't making good contact, then you could easily have a situation where the CoF is too low to stop the few wheels in contact from slipping. 

In the interests of keeping the argument on solid ground, I'll ignore your other comments ;-)


----------



## Greg Elmassian (Jan 3, 2008)

"if the CoF is somewhere marginal"??? 

The coefficient of friction between steel drivers and steel rails is a constant, and if it was always marginal nothing would work. 

The coefficient of friction is not changing in the example we are talking about, that the tractive effort is driven solely by the coefficient of friction and the normal force (downwards) on the drivers. 

I don't know why you persist in making guesses or theories when this is all a well known fact in physics and locomotive design. 

It seems pointless to continue this, live in your own reality. 

Greg 

p.s. you are well to ignore my comments, since it was your negative comment in the first place that prompted it. 

Over and gone... 

Greg


----------



## steamtom1 (Jan 2, 2008)

*In our instance, it seems to me that the coefficient of friction between the wheels and the rails is always a function of the amount of residual oil, (both steam and lubricating), that remains on the tracks.*


----------



## aceinspp (Jan 2, 2008)

First off I'd like to thank Tom for going way out of his way at a time most of us would never had gone with his issues he had when he got home. Thanks for the info. Kevin it took awhile for you to finally get to the loco and make the observation and finally provide some good feed back Thanks. Little prods do work. For some others that have responded and saying they runs there loco with out issues. Well that can happen seeing how you most likly run on a table and no switches. I'm sure if I had that scenario l'd not see a problem either. My RR is all free floating track with numerous turnouts and some S curves with plenty of tangent in between curves. 99 % of the curves are 10ft diameter and the remainder 8 ft. 

I have readjusted a couple of track locations and removed a switch in a critical area also. Gage has never been an issue had it been I would have brought it up as the other wheels sets would have dropped in also. I spent 43 years in the rail industry with a track back ground and doing accident investigations. I will test run the loco tomorrow if time permits other wise it will not be till next week. Later RJD


----------



## jfrank (Jan 2, 2008)

Posted By aceinspp on 09 Apr 2013 05:37 PM 
For some others that have responded and saying they runs there loco with out issues. Well that can happen seeing how you most likly run on a table and no switches. I'm sure if I had that scenario l'd not see a problem either. My RR is all free floating track with numerous turnouts and some S curves with plenty of tangent in between curves. 99 % of the curves are 10ft diameter and the remainder 8 ft. 

Later RJD




Well aren't you special!


----------



## East Broad Top (Dec 29, 2007)

When you do get a chance to test the loco, please take some close-up video of the wheels on the rails where you're having issues so we can try to pinpoint what your troubles may be. If you could, pay particular attention to the places where the loco enters and exits the curves so we can see what the wheels are doing on the straight and as it transitions into the curve. 

In the mean time, set the loco on some 4' radius track and see how easy it is for you to rock the loco side-to-side, and see what the middle drivers do when you do that. My money's still on the springs on the #1 and #4 drivers being soft enough so that the loco's rocking outwards on the curve, and pushing the blind drivers below the railhead. If your loco--when fully watered--is such that the blind drivers hang suspended above the rails, that's about the only thing I can think of which would cause them to fall below the railhead on a curve. 

Given the discussions we've had in the past, I can't imagine your ground-level, floating track is that much worse than an elevated track, which actually aren't always as smooth as one might suspect. Take a look at the bobbing and weaving of my loco on the DGRS track. The camera was sitting on the tender, and the track (at that time) was likewise just floating in the ballast. (It's since been rebuilt to add a 3rd track, with the ballast bed replaced by timber deck boards and rolled roofing.) 

We'll get this sorted out for you one way or the other. 

Later, 

K


----------



## Larry Green (Jan 2, 2008)

"Table and no switches"???? My raised track here in Vermont floats on the ground and is subject to seasonal frost heaves, so it is far from perfect. From experience, I have found it doesn't have to be; just adjust any rough spots each Spring. Heavy, long wheelbase engines, including a K-28 and a GS-5 running here do just fine. As does my BF 13 (ex EBT 12). 

Kevin, from your last post, you have much more patience than I have with folks who ask for help, but with an attitude. This is a hobby site, not a corporate board room ( I have experienced both). Just wish some folks left their "attitude" someplace else. 

Larry


----------



## Nick Jr (Jan 2, 2008)

WHO SAID MLS CAN'T BE AMUSING


----------



## Pete Thornton (Jan 2, 2008)

that can happen seeing how you most likly run on a table and no switches. 
I don't think Roger's RGSEast can be described as a table. And as I already mentioned, my RYM electric Mikado frequently hits the dirt. 

RJ - why are you making such suggestions? Just general frustration with your unique problems?


----------



## aceinspp (Jan 2, 2008)

Apparently Pete you where never an investigator as I was . You ask any and all questions to find answers. Nope no board room just plain and simple wanting answers and apparently some folks don't understand as they think they do. As said it's a hobby and one ask for help don't give run around questions and you will not get neg feed back. Later RJD


----------



## Pete Thornton (Jan 2, 2008)

Posted By aceinspp on 14 Apr 2013 03:20 PM 
Apparently Pete you where never an investigator as I was . You ask any and all questions to find answers. Nope no board room just plain and simple wanting answers and apparently some folks don't understand as they think they do. As said it's a hobby and one ask for help don't give run around questions and you will not get neg feed back. Later RJD 

My comment was aimed at the style and courtesy issues, not the substance. I ask questions all the time. 
If you are still interested, I checked my Mike when I got back to MD. It had much the same situation as Kevin's when sitting on the shelf - the left front blind driver wasn't touching, and neither of the RH blind drivers touched. While running at Cabin Fever with a load of water, I repeated the 'receipt paper' test and the two RH drivers were hard on the rails. The LH front blind driver was still not touching.

It seems the loco has a problem putting it's LHS #2 driver on the rails.


----------



## aceinspp (Jan 2, 2008)

As I mentioned Pete you get the courtesy given for unwanted comments. Do your home work make good observations before posting and you will get the courtesy. Yes and you made the same observations as I did in a way. I did notice when adding water it did sit different but still had some day light. Later RJD


----------



## Totalwrecker (Feb 26, 2009)

We have homework?


----------



## chuck n (Jan 2, 2008)

Gentlemen, I do not have an Accucraft EBT anything. I do have three Accucraft locomotives (all electric, K-27, K-28, and C-19). All but the K-28 ran around my layout flawlessly. The K-28 couldn't make a single loop. After a year plus of frustration I talked to somebody and he suggested removing some of the springs from the drive wheel suspension. I took out two of the three springs I each journal(?). I left the center spring. This solved my problem, no derailments since. Check the springs to see in they flex. Mine didn't. Only by removing some did the axles actually move up and down like they are supposed to. Chuck


----------

