After doing other things, I push these tank cars I built from kits and notice that they often derail. Sometimes the derailment happens on straight track and other times curves. Can they not handle 30" curves? What should I do to make them function properly? Add more weight? Replace the wheels? Speaking of, I suspect something weird there esp since the wheels are in alignment.
Interestingly, I tested some manufactured Atlas 65' tank cars and they navigated the curves flawlessly and I check to ensure the entire track is aligned properly. This indicates the curve is unlikely the issue.
Rolling stock likes to hav a "three-point" suspension. Such as, set the pivot screw (bolster) on one truck slightly snug, but loose enough to allow free pivoting, and quite loose on the other so that the trucks can allow for uneven track.
Also be sure to have an NMRA wheel gauge and check each pair of wheelsets.
Good Luck, Ed
I have several examples of the Atlas cars, as well as their Walthers counterparts, the latter both RTR and built from kits. I have no derailment problems with any of them. All of mine that came with plastic wheels received 36" machined metal wheels to replace them, either ExactRail or Intermountain. They can easily handle a 30" radius curve.
Also note the bolster/end frame assemblies are easy to mount crooked, which could prevent the trucks from sitting flat against the rails. If that happened, perhaps the wheels aren't all in proper contact with the railhead. Any such misalignment could be made worse if the truck screws are too tight.
In contrast to many, I'm not a believer in the "three point suspension." That was worthwhile in the old days of sprung trucks, but can induce derailments with rigid trucks on certain cars. I usually make one truck tighter than the other, but try to allow at least some sideways movement in both of them. If a car proves to be derailment prone, often loosening the screws just enough to allow both trucks to rock sideways a bit will cure it.
Rob Spangler
Hi kasskaboose:
The curves are not your problem. Hundreds of thousands of model railway cars the world over handle curves just fine. Yours should too.
I would start with some very basic checks in order to identify what is wrong.
Your cars should have some weight to them. The NMRA formula is 1 ounce plus 1/2 ounce for every 1/2" of car length.
Second would be to make sure that the wheels rotate freely. Give the wheels a flick with your finger. They should rotate smoothly and should spin for a couple of seconds at least. If they don't, you should get your hands on a truck tuner like this:
http://www.micromark.com/HO-TRUCK-TUNER,8241.html
Next, put each truck on a very flat surface like a pane of glass. All four wheels should be touching the glass. If not you may be able to twist the truck enough to get it to sit level, but Delrin has a memory so they may not stay flat. Personally, I doubt that warped trucks are the problem (i.e. it's unlikely that all your trucks are warped, but who knows). At least test them so you can cross that off your list.
Then put the trucks back on the cars and test them on the glass again. All eight wheels should be touching the glass. Rock the car around a little bit and see if any of the wheels lift off the surface. If the car doesn't sit level then, as somebody mentioned, it may not be assembled properly. Hopefully not. If it's all glued together it would be a pain to correct that.
Here is where you can get into some discussion about how tight the trucks should be mounted to the car body. The common assumption has been that one truck should rotate freely but not rock on the bolster and the other truck should be free to pivot in all directions. However, as Rob Spangler points out, that may be a hold over from the days where all the trucks were sprung. I think it is safe to say that each truck should be free to move, but you don't want them so loose that the car body wobbles back and forth as it runs down the track. I think Rob's suggestion of having one truck somewhat loose and the other a bit more loose makes sense.
You should make sure that the couplers are at the right height and that they pivot freely too. Don't forget to check the locomotive coupler and/or the cars that are leading the tankers as well.
I hope you can solve your problem. EDIT: I'm sure you can solve your problem!
Dave
I'm just a dude with a bad back having a lot of fun with model trains, and finally building a layout!
I follow pretty close to what Rob does. I had issues with Intermountain hoppers. Turns out the couplers were binding, so my advice is check the couplers and make sure they move freely and spring back to center.
Tom
Do these have metal axles or plastic? Member of the club had a car with plastic axles. There was a ridge of flash along the axle, and there was some slop between the bolster pin and the truck. In certain alignments the truck would slide a bit on the pin and the flash would hit the coupler box, causing a derailment.
What to do about derailments?
Derailments can be the trackwork or can be something wrong with the car. In stubborn or questionable cases, I keep statistics. I put a small post-it note on the roof of the derailed car AND at the place the derailment occured. After a day or so of running, you will have post-its building up on either the car or the trackwork.
Looking at the car. Most manufactured rolling stock is too light. A scale is needed. Side track, I went to buy a postal scale at the stationary store long time ago. The very nice lady behind the counter explained that she didn't carry them anymore because the people who bought them were all drug dealers. So I bought a nice little spring balance scale at a kitchenware shop. I have at least a dozen cars where weighting up to NMRA standards solved derailment problems.
Check gauge on all the wheel sets. You need the NMRA gauge for this. If out of gauge, you can usually twist a wheel a tad and work it back into gauge. While you are at it, look for bits of crud stuck on the treads, bits of flash, or a buildup of wheel cheese. I've seen wheel cheese buildup so bad that the flanges disappeared. Check for free rolling, give the wheel set a flick with a finger and a good one will keep rotating for at least a few seconds.
Check the trucks. They need to swivel freely without catching on underbody detail or coupler boxes. I still do the "three point suspension" thing, one truck tight one truck a bit looser. You can replace overly floppy plastic truck retainer pins with 2-56 machine screws. If necessary, plug the holes in the car bottom with pieces of sprue and drill the plugs to accept the screws. Check that the trucks run straight along the track, not katty cornered. Katty corner can often be fixed by reversing one wheel set in the truck.
Check the couplers. If too low, the gladhand will catch on the trackwork. That's a surefire derailment every time.
Finally eyeball the car on the track. It should stand up straight, no leaning to either side. Roll it back and forth, it should run smoothly, straight, and no jiggling up and down.
Good Luck.
David Starr www.newsnorthwoods.blogspot.com
I assume these are the Walthers tank cars with no center sill? One "problem" with the long Walthers cars is that it is possible to introduce a slight "skew" due to very slight misplacement of the end bolsters during construction. They seem to be setting just fine but once the cement has dried, things turned out to be slightly off. Other than attempting to pop them off and re-cement this can be a hard problem to solve.
Also, I do think that for certain long cars, just having weight to (or above) NMRA standards is not enough -- concentrating the weight over the trucks is meaningful, because the weight is relatively high in the car. A weight in the bottom of the tank is a better idea than a sheet steel weight.
Again if the cars are assembled there may be no easy fix here. But ironically the Walthers design of cementing tank halves is often so poorly done that they can be snapped apart with a knife blade.
Dave Nelson
I think more information is needed..
Are these 65' tank cars built from a kit or RTR? Forgive me but, are you sure they are 65'? Walthers doesn't list any 65' tank cars on their "new and improved" web site but,lists a 55 footer. The 65' was offered as a kit..
I had the same issue with my RTR 53' tank cars.Its a easy fix but,I'm not sure of the 65' tankcar kit..
Larry
Conductor.
Summerset Ry.
"Stay Alert, Don't get hurt Safety First!"
Thanks for the fantastic advice all. What a relief that others have experienced derailments with cars. I might have resolved the problem after loosening the screw that holds the trucks a bit. how to preven the cars from wobbling? Perhaps that won't happen often when the cars are powered with a locomotive instead of me pushing them?
Larry: Yes, the cars are older 65' tank car kits.
I checked the wheels and weights and both conform to NMRA standards. Would adding more weight to the bottom (by the trucks) become overkill?
Thanks all!
Let's see..I'll share this.My 53' tank cars derailed so,upon checking I found a truck screw was too tight.I simply tighen the screw completely down and backed the screw off my normal 2 turns.
As far as the 3 point suspenion I hate it. I tried it several times on different brands of freight cars and each time the car went down the track waving at me. I still use the old fashion tighten the screw completely down and back off 2-2 1/2 turns.
Any time you can operate 8-10 hours a day for 6 days during the county fair and have zero derailments you doing something right.
BRAKIE ... I still use the old fashion tighten the screw completely down and back off 2-2 1/2 turns.
... I still use the old fashion tighten the screw completely down and back off 2-2 1/2 turns.
2 1/2 turns with a #2-56 screw is .045 clearance / float. That seems excessive to me.
I haven't read all of the replies, so maybe this has already been suggested but ream the axle points on the trucks and provide a spot of oil on each reamed area of the trucks. That will eliminate drag which causes derailments.
Rich
Alton Junction
Old Thumper BRAKIE ... I still use the old fashion tighten the screw completely down and back off 2-2 1/2 turns. 2 1/2 turns with a #2-56 screw is .045 clearance / float. That seems excessive to me.
Could be,maybe, perhaps..
Last time I mention I tighten the screw completely down and back off 1 1/2 turns the replies wasn't pretty and I don't want to go through that again but,2 -2 1/2 will work and that seems to be the norm use by those that made replies in that topic..
I like it where my trucks is tight but,still turns freely. That method has served me well since the late 50s-I was 10 years old when I started building BB kits and learn right away there was lessons to be mastered in building a BB kit if you wanted a derailment free car.
kasskabooseI might have resolved the problem after loosening the screw that holds the trucks a bit. how to preven the cars from wobbling?
The kits came with plastic wheelsets. You may be able to keep a car derailment free with properly gauged plastic wheels, but it's almost guaranteed to wobble. You can eliminate wobble with machined metal wheelsets like Intermountain or ExactRail in the original Walthers trucks.
kasskabooseI checked the wheels and weights and both conform to NMRA standards. Would adding more weight to the bottom (by the trucks) become overkill?
In my opinion yes. I rarely add extra weight, especially not to cars that already meet the recommended amount. From my experience, good wheelsets and properly tuned truck mounting are the major factors ensuring smooth operation.
CHECK the distance between the coupler face and the kingpin. The further the kingpin is from the coupler face the greater likelyhood of issues. Both cars should have a similar distance, if one has the king pin up close and the other further back that can be a source of problems.
65' cars ought not to have such issues like an 85' pax box but it is just another thing to look at.
And remember that where the car falls off the track might not be where it first derailed. It may have had an issue at a switch point half way round the layout on only became obvious on the curve.
LION has also discovered that there are buff and slack issues with some cars, especially in the buff mode of operation (pushing the cars) Forces may be moving in a direction that you do not anticipate.
On Subway layout of LION, the powered cars are in the middle of the train, so half the trains is in stretch mode, and the other half in buff mode.
ROAR
The Route of the Broadway Lion The Largest Subway Layout in North Dakota.
Here there be cats. LIONS with CAMERAS
Was pulling my hair out (what's left of it anyway) with a highly detailed RTR woodchip hopper continually derailing. Turned out the fancy undercarriage brake gear was preventing one of the trucks from pivoting enough, but was only happening on smaller radius curves.
Good luck and regards, Peter