Got yet another one for my Forum friends: Does anyone have an idea why a car truck would be lifting itself off the rails? The car is question is a Tyco crane that has been converted to ride on Athearn 6 wheel passenger trucks. One truck lifts off when it is in the trailing position but when it leads, the car is just fine. The other rides properly. The track is clean with no ballast or any other dirt on the track. (I replaced it due to a bad joint.) The spot is where the curve changes direction. The only thing I can come up with is that the trucks are too tight in the modified holes. As usual any suggestions would be most welcomed.
I agree that the trucks may be mounted just a bit too tightly. Loosen the tighter screw by a quarter turn or so. Play with this until it works.
You also mentioned "where the curve changes direction.". Is this an S curve? These can create problems for longer cars. The odd twisting required to get longer cars through the curve when coupled to other cars, moving for the moment in different lateral directions, often results in derailments. S curves are trouble, and their limitations must be recognized. Many avoid them for this reason.
It takes an iron man to play with a toy iron horse.
I loosened the screws on the trucks and that didn't help. What I was meaning was I made the holes in the Tyco underframe a bit bigger to give the trucks a bit more flex. It is an S curve in 22 R. It is a necessary evil for the spot. That particular corner is wider than the section that it attaches to and is needed to make an industrial area.
Does the car make it through the curve by itself, just pushed by hand? Pulling or pushing the car in a train or just with a loco will highlight issues with the S curve.
I attached one of my GP20s to it and it seems to be running through the curve just fine. (One must remember not to leave wood chisel on right of way however. Temporary short circuit.) I did expand the mounting holes from a #14 bit to a #10 and that seems to have helped.
Late to this but:
Have you considered that being a crane car one end might be heavier than the other, and the lighter end lifting if trailing.
FRRYKid...I did expand the mounting holes from a #14 bit to a #10 and that seems to have helped.
I'm not familiar with the Tyco crane, but the Athearn 6-wheel passenger trucks don't seem to me to be an appropriate choice, due to the large "boss" atop the truck which allows the attachment to the car to be a screw driven down from inside the passenger car, rather than up through the truck. Athearn's 6-wheel Buckeye truck might have been a better choice, as it mounts in the same manner as do most freight trucks.
Your use of numbered drill bits threw me at first, as it sounded as if you were using especially over-sized screws, until I realised that this was to accommodate the boss on the passenger car trucks, which is .1770 in diameter.
Expanding the mounting hole will help only to a limited extent, as the portion of the screw which passes through the truck has no play at all through its .287" length, which terminates in a fixed thread at the mounting point.
The two options I would suggest is to either remove the boss from the trucks completely, and alter the mounting points under the crane to solid ones, then drill the holes through the trucks to a clearance value for a 2-56 screw (#42) and then drill and tap the solid-block mounting points for 2-56 (#50).
The other option would be to use the Athearn Buckeye trucks, which come with a clearance hole suitable for a 2-56 screw, and alter the mounting points as mentioned above. Either will then afford more available rocking motion by backing-off the mounting screws in small amount.
The Athearn passenger car trucks track well enough on those cars due to the longer length of the passenger cars, but don't fare so well on the shorter wheelbase of the crane.
Wayne
Hello All,
I have a few questions to possibly help you resolve this problem.
Now that I have plenty of free time, I got out one of my many vintage Tyco crane cars.
To give some history on this particular car- -the main pivot of the crane sheared off and I had to replace the pivot with a nylon "top-hat" bearing, nylon washer and bolt with a nylock nut. Because of the new hardware I had to drill a hole through the metal weight and floor of the car.
FRRYKidThe car is (SIC) question is a Tyco crane that has been converted to ride on Athearn 6 wheel passenger trucks.
One question is, what prompted you to convert the Original Equipment Manufacturer's 6-axle trucks to the Athearns?
Did you reuse the OEM wheels with the tapered axles with the square section in the middle of the axle?
On my car I removed the OEM wheels, used the Micro-Mark truck tuning tool and replaced them with Intermountain Semi Scale 33-inch metal wheels.
When replacing the wheels I noticed that the OEM wheels, when rolled on a flat surface, came to a halt. This seems to be a product of the square section in the center of the axles and not flat spots on the plastic wheels.
Because of the rigidity of the OEM trucks I could not fully seat both ends of the truck tuning tool in the middle bearing seats. I had to use this tool at a skewed angle.
Because this is the middle set of wheels I thought that more side-to-side play would give the trucks more latitude through the "S" curve created by two back-to-back Atlas snap switches.
I also cut off the TALGO truck mounts and body-mounted the gearboxes and couplers.
After reassembling everything this car has no problems negotiating the 15-inch curves and back-to-back Snap Switches that constitute an "S" curve, both being pulled and shoved.
I suspect that it might be the aftermarket trucks that you retrofitted to this car is the culprit.
Do you still have the OEM Tyco trucks?
You might be able to re-install the OEM trucks, without the TALGO gearboxes, depending on the amount of "surgery" you performed on the original car.
If not...
You could use the crane portion of this car and kitbash an overhead traveling crane or remount it to a more functional flatcar.
Hope this helps.
"Uhh...I didn’t know it was 'impossible' I just made it work...sorry"
I have a similar spot that wreaks havoc with 3 axle trucks In one direction. Check the gauge of the axles and track. Also check to see how level the rails are. that spot has been a nuiceness for years. Only two weeks ago i found that the outside rail was .020 lower than the inside rail on that curve in
that spot. Allowing the 3 axle trucks to roll right off the track. For me it is a simple fix of lifting the rail, gluing .020 strip on the bottom, paint and relay the rail. I found the problem by very carefully observing. There was a gauge issue (to wide spacing on the axles) but that wasnt the whole problem. the elevation difference revealed it self by flashlight, and viewing at low level from one angle. Not sure how your track is down , but shims under the ties might be needed.
So check the gauges and try these ideas before looking at having to shim the track. try metal wheels, they do have an effect on tracking. And do improve it. The crane could be just to light Also. A little wieght might help
Shane
A pessimist sees a dark tunnel
An optimist sees the light at the end of the tunnel
A realist sees a frieght train
An engineer sees three idiots standing on the tracks stairing blankly in space
jjdamnit One question is, what prompted you to convert the Original Equipment Manufacturer's 6-axle trucks to the Athearns? Did you reuse the OEM wheels with the tapered axles with the square section in the middle of the axle?
The original trucks were replaced as a clip was broken on one of the trucks. As for the wheels they are the metal wheels that came with the Athearn trucks.
As to the question as to why I used the passenger trucks instead of the buckeyes, the buckeyes don't have an offset mount like the passenger trucks do. The stock Tyco truck's mount was offset.
The other thing was I replaced all 4 pieces of the corner which also has helped with the problem. I haven't secured the track back down but that is part of the plan for Monday or Tuesday.
Thank you for your response.
Having many vintage Tyco cars I understand the problems with broken truck clips.
FRRYKidAs to the question as to why I used the passenger trucks instead of the buckeyes, the buckeyes don't have an offset mount like the passenger trucks do. The stock Tyco truck's mount was offset.
I don't know if this will help now but the Athearn Buckeye trucks I have do have offset mounting holes.
Hope you got the passenger trucks to work. If not you might try the trucks I listed above.
FRRYKidThe other thing was I replaced all 4 pieces of the corner which also has helped with the problem. I haven't secured the track back down but that is part of the plan for Monday or Tuesday.
How sharp a radius is the track?
Some 6 wheeled trucks don't play well on sharper curves.
This might not be the ideal solution but have you considered removing the center set of wheels and just having the 3 axle side frames for appearance?
Good luck with the track replacement.
I'm not going to repeat what's already been said, but I do have another thought. Could it be a weight issue? (I.E., not enough) Is the car in question up to the NMRA recommended weight? https://www.nmra.org/sites/default/files/standards/sandrp/pdf/rp-20.1.pdf Or are you pulling any heavier cars behind it? The reason I ask all of this, is I have some USRA hoppers that had this problem. Especially with any cars behind them. It turned out that they were too light, so I added weight and it corrected the problem with no further modifications needed.
I set up an S-Curve of Kato Unitrack and make sure all equipment will go through it.
On my layouts, I learned early that curves of 24 and 22 inch radius are best laid with Atlas sectional track. That way you KNOW there is no spot where the radius gets forced a little tight to make it fit or by mistake.
Everything I run, even my Bachmann 2-8-8-4 will go through a 22 inch S-Curve with no tangent track.
-Kevin
Living the dream.
I checked the weight on the car and it is fine, even a little bit heavy. (I was surprised at that.) The curve is laid with 22"R Atlas sectional track. I secured the track back down last night and the car still rolls through the curve. The only car that would trail it is a little light but light cars can go at the end of the train without problems.