Hi All,
I have a derailment issue that is effecting one locomotive, A Bachmann F7-A. It is occuring at a rail join (18 radius) on an incline. There is nothing special about this join. I can’t find any obstructions, I’ve checked it with an NRMA gauge, the rail joiner does not seem to be obtruding abnormally and I can’t find a kink.
I’ve tried filing it to make sure everything is smooth. Nothing works. It derails at slow speed 4 times out of 5 when going up hill. Down hill is no problem. When it happens the front truck kicks left and goes over the outside rail.
The track in question is Atlas code 83 18’ sectional.
I am going to enclose a couple of photos in the hope that someone can give me some tips or ideas.
Thanks,
Steve
Picture of spot where it happens above.
Picture of F7-A derailed over the rail joint. As far a I can tell it happens either right on the join or about 1/4 inch before. There is nothing on the bottom of the loco catching anything. My prime suspect was that it was riding up on the joiner. I filed that down as much as I could but it didn’t help.
If you’re convinced there’s not a lateral kink, also check that there’s not a significant “twist” or roll from level across this area. A short level that you slide along should give you an idea, though a small (round) bubble level is easier to utilize. I got one for less than $2 at good old Harbor Freight. (It has a lifetime warranty, so I guess I can FedEx it back to China if the fluid leaks out). Anyway, a significant twist, especially in one direction, can help the derailing wheel climb over the rail The engine may be contributing, but it’s a good tester. If you have a twist, try some shims to smooth that out and see if it helps.
I’m going through the same issue at one track spot with my most cantankerous steamer. When backing up, the rear driver likes to climb over the outside rail. My problem is a combo of an overly sensitive engine (changing springs may help), but also at least 50% of the problem is a mild joint kink with an added axial “twist”.
If there might be any kink at all, you might try temporarily spiking the track in the unkink direction around the joint.
LION RULE No. 1.53826
The problem is not where you think it is. It may be further back along the railroad, and this is where it comes off of the track. Check the whole area carefully. Put your nose in the roadbed and watch it.
The other thing to look at is the locomotive truck. Maybe IT is binding or does not have a free enough swing and/or tilt to it. Make sure that the truck swings and tilts freely in all directions.
ROAR
f you’re convinced there’s not a lateral kink, also check that there’s not a significant “twist” or roll from level across this area.
Paul,
ahhh… I do indeed have a twist or a roll from level at this spot, and it is what you would call significant. and… unfortunately it is a roll in the wrong direction. I built the incline using cookie cutter and checked the level before installing the roadbed so either I goofed or something has shrunk due to low humidity in my basement over the winter.
I tested everything with multiple locos before completing the scenery. However, after posting this I went back and tested some other loco’s. None derail, but they all get near to it…
Based on your advice I tried something. Since this is a 4*8, I elevated the end shown by one inch with some wood blocks. This causes some super-elevation going into the incline, that goes to dead level where the roll occurs. The F7-A still derailed. There may be a kink that I cannot see. Can you please explain what you mean by "spiking the track in the unkink direction around the joint".
I fear is there is not a simple solution to this, I am going to have to rip out the section and replace it, with all the pain and suffering that goes with that (since the landscaping is complete).
Thanks for your help and suggestions.
Steve
Check the area where the rear truck is at during the derailment. The locomotives rear truck may be leaning or dropping down and causing the front truck to raise slightly.
LION,
I’ve had my nose so close to the roadbed that the roadbed gets wet. Your point however, is well taken. I made sure I checked a good 6-9 inches before it derails. The trucks also swing freely and tilt fine.
Jim/LION,
The area between the front and rear truck is where I have the change in level from a slight super-elevation to well, I’m not sure what to call it, but its the opposite (thanks to Paul for getting me to check this). This could indeed cause the lefthand front truck to ride high and its possibly the cause. Confirming that however requires me to lift the track and shim it to correct the problem and I didn’t want to do that unless I was sure that was the cause. What is perplexing me is that I can push the locomotive through the area just fine, its only when its under power.
Thanks,
Steve
Hello Steve,
I have had similar issues with a Bachmann H16-44 that would only derail at one particular point when pulling a consist of cars. After messing with the locomotive w/o success I closely examined the track and found a slight dip on one rail where the joiners met. A small shim raised the rail level to the adjacent rail and the problem went away.
Your F7A under load in a 18" radius curve may just have enough torquing of the frame to have the wheel ride up ever so slightly and find a very minor imperfection.
One other thing to consider. I don’t know if you are using the newer Bachmann unit or and older Plus model. I noticed the older ones were a lot heavier. A newer one with a train behind it may be “underpowered” for the assignment, meaning the front of the locomotive would be rising up. Under normal circumstances not a problem but it would definitely find that one little spot to derail every time. If you suspect this is the case, try adding a second locomotive.
Hope this helps
John,
Its one of the new Bachmann Sound Value F7-A’s. It was only released a few weeks ago in the Pennsylvania scheme. The problem is happening under load or no load. I will try the shim method and see if I get results. The problem I will have doing that I have the area fully ballasted and there is a layer of caulk between the roadbed and the track. This is the first layout I have built and when I laid the track I was an extreme newbie. I did have a bunch of derailments in other areas and managed to catch them and fix them, but completely missed this one. I know now I have a twist so a dip is my most likely culprit. If all else fails I will rip out the section and replace it with some left over flex track. I used sectional in this area as I am building the Virginian and that was what MR used.
Thanks for the advice.
Steve
Some engines just don’t like 18" curves. If the track work is not absolutely perfect they act up.
Excellent ideas/comments so far…
Assuming the track is within gauge, and not kinked horizontally OR vertically, and the joiners are not hitting the wheel flange, it is then time to check the loco.
There could be a bind in the turning of the truck, or a wheel could be out of gauge. If this is the only piece that has a problem there, then it is likely the loco.
One thing that has worked well for me is to get a piece of clear plastic, shaped like a flat car, with a good truck on either end. Moving this slowly over the joint will indicate any unusual movement if it is indeed, the track.
Good Luck!
Problem solved thanks to the excellent suggestions…
Shimming wasn’t as hard as I thought. Once I wet the area the ballast and track released. First I put a shim under the outside rail (derailment side) exactly where it derailed. Would you know it, the derailment just moved 1 1/4 inches up the track.
So I put a shim 1 1/4 inches before the derailment and the problem was solved. I still have a slight twist/roll (change in level), but it is not happening near the rail join now. I think eventually I will have to deal with the whole section and make it level, but for now I am happy. [:D]
Thanks,
Steve
Using only your picture as a guide… the white arrows show what appears to be a big difference in the superelevation of the track. If this is in fact true then it is likely the cause of your problem.
Alan,
You are spot on. Thanks for taking the time to detail it. When I put a shim where you show it too low it just caused the derailment to move a bit up the track, so I put a shim just behind the rear wheel of the front truck. I will eventually have to shim the whole area.
Cheers,
Steve
I just had the same problem with a new steamer, turned out that I had to file the inside rail a bit, the difference could not be felt and hardly seen but it was enough to cause derailments.
Something nobody told me, and nothing I ever read on benchwork mentioned it…but cookie cutter with grades on curves - especially 18" radius curves - automatically produces sections of positive and negative super-elevation of the track. You have to twist the plywood with the risers and cleats to prevent this from happening. On my first attempt at cookie cutter construction with 4% grades, 18" radius curves, and 1/2" plywood being cut, I had to add joists, risers, and cleats to get a cleat every 10"-12" on the curves with grades to induce the required twist in the plywood.
Before I added the extra risers and cleats, I had a 180 degree curve of climbing 18" radius with a 2" rise over the curve. There was a significant negative super-elevation for the 1st 90 degrees, the curve was level at the mid-point, and had positive super-elevation over the 2nd 90 degrees. Totally disconcerting visually, and I swore at all the books and magazines that never mentioned the issue. Add any track imperfections to the constantly changing super-elevation, and you have guaranteed derailments.
just my experiences
Fred W
I can attest to what Fred says about forcing plywood into the proper super elevation. The problem was especially pronounced on a slot car track I built years ago. Many closely spaced risers and lots of screws were needed to force even thin luan sheet to the banking I wanted through curves.
Fred,
Mine goes from slight negative to level at about 45 degrees then gradually positive until about 70 degrees then moves within a short space (2 inches) to negative for the rest of the curve. The largest positive to negative happens right over a track join. In retrospect I now think I know what is cause of the dramatic switch at 70 degrees. The Virginian has a section on this rise that is to support a mountain. My theory (which will never be proved since its now buried) is that I never leveled that correctly which put torque on the rest of the curve. But what I have learned is what you learned. Level everything, level it again, then re-level it before its locked in. This was essentially a starter layout for me to learn how to model so lets hope I can remember to apply the learnings when I build the next one some time in the future.
Cheers,
steve