Constantly derailing...

Affiliate Disclosure: We may receive a commision from some of the links and ads shown on this website (Learn More Here)

KB02

Well-Known Member
#1
I have two cars that are constantly derailing at various points on my layout. These are the only cars that derail at these points, and they derail a different points on the layout. The rails are in gauge as are the wheels. One of the cars derails in the middle of a section of flex track in the middle of a tunnel (I watched and the rear most wheel set starts to roll up on top of the inner rail and then pops over the top).

What should I look for?

No other car gives me issues in these areas. I have changed wheels, changed couplers, and done everything short of changing the trucks themselves. What am I missing?
 

chessie_system3

Well-Known Member
#2
I found that if there are any dips in the rails it can cause a derail. It is what killed my last layout. My current build I've had to shim spots where derails have happened. Mostly because one rail is lower than the other.

Justin
 

santafewillie

Well-Known Member
#3
You may need to add some weight to your cars. NMRA recommendation is 1 oz + 1/2 oz per inch of car. Basically a 50' boxcar that's about 7" long, needs to weigh 4 1/2 ozs. If weight is needed for an enclosed car, glue pennies inside, 10 pennies weighs 1 oz. Other things to check are; as Justin said, look for dips in the track, check for free movement in the trucks...not too tightly attached, and also look for warped trucks.

Willie
 

Selector

Well-Known Member
#4
In no particular order, but all quite possible, maybe even two or three of them acting in concert at the same time:

a. trucks don't swivel enough...look for something they abut against at their extreme movement;

b. couplers " " "

c. worn couplers whose grip loosens at extreme angles;

d. wheelsets out of gauge;

e. wheelsets on the same truck whose flanges do not align when both axles are pressed to the same side of their journals;

f. curves too tight for the couplers and truck swivels to manage; and/or

g. uneven rail heights, too much super-elevation, or a kink/spotty solder that leaves gobs of solder behind.

That's why we have a rule in the hobby to ensure hidden trackage is simple and 'bullet-proof'. NEVER place a turnout or a crossing/crossover inside a tunnel or a helix...unless you like aggravation and self-recrimination.
 

KB02

Well-Known Member
#5
That's why we have a rule in the hobby to ensure hidden trackage is simple and 'bullet-proof'. NEVER place a turnout or a crossing/crossover inside a tunnel or a helix...unless you like aggravation and self-recrimination.
Yeah, I learned that one the hard way. (Speaking of which, I need to get my kid down to the layout to reach into a tight spot to grab a tool that I can't reach after it fell in a hole... I've had him pull flat bed cars out of the hole before, too. Hence the aforementioned lesson.)

----------------------------------------------

On a side note, I seem to have found a way around my problem - temporarily, at least. I moved the two troublesome cars within the consist and turned one around. For whatever reason that seems to have done the trick at the moment.
 
Last edited by a moderator:
#6
If weight is needed for an enclosed car, glue pennies inside, 10 pennies weighs 1 oz.
Willie
I used automotive wheel weights. They are readily available in 1/4, 1/2 and 1 ounce weights and come with an industrial quality sheet adhesive on the back side. You can spread the weight more evenly if you so desire and there is no potential glue mess to deal with. You can buy them an nearly any auto parts store.
 

tootnkumin

Well-Known Member
Staff member
#7
Your first post suggests a track gauge narrowing, or twist, dip, rise at the point it derails there, problem, if your wheels are dead right in gauge and with enough side to side rocking movement. If you can't get at the track to check of fix it, maybe adjust the wheels doing the climbing/derailing to a fractionally closer gauge. Check also the side frames on the truck to make sure one or both aren't bent. I had one on an OBS car that was off vertical, only really detectable by looking along it from the end. Being it was a Walthers it had to be dismantled to correct it.
 

Iron Horseman

Well-Known Member
#9
On a side note, I seem to have found a way around my problem - temporarily, at least. I moved the two troublesome cars within the consist and turned one around. For whatever reason that seems to have done the trick at the moment.
That makes me think of a couple things. This "way around the problem" could indicate the trucks are too tightly mounted such that they don't pivot or rock enough (Selector had this in his list above). They should move some on all three axis - yaw, pitch, and roll. Also perhaps there could be some sort of obstruction (brake cylinder, frame element, etc) in one direction that prevents a truck from pivoting enough , but in turning the car in the consist it pivots the opposite direction. This is usually a much bigger issue with passenger cars because of all the extra equipment on the truck itself and stuff mounted under the car floor.

random thought - Track gauge should be a tiny bit wide on curves.

Also brings up two questions.
How long are these cars compared to the others in the consist? Do these cars have couplers mounted on the trucks? Climbing the inside rail is a symptom of the train being pulled more on a cord rather than the tangent.
 
#10
I had a problem with cars derailing in the long tunnel on my layout. It happen to several cars, but not all the time when running through the tunnel.

It turned out to be a track nail that worked itself up from the center of a plastic tie and was catching on the coupler glad hands.

A real simple problem and an easy fix.

Greg
 

montanan

Whiskey Merchant
#11
Quite a few ideas were posted for you problem. I had a similar situation years ago. It drove me crazy. I finally found out the the trucks were just so slightly too tight. One should be able to pivot freely and also have some sided to side movement and the other just free to pivot. cured the problem.
 

KB02

Well-Known Member
#12
It's been a while since I posted this thread and, honestly, since moving and turning the cars worked, I haven't revisited it.

Yes, I do have a gauge and everything measures out within spec. All my cars have body mount knuckle couplers. And the two cars having the issue are shorter box cars. Weight and truck movement will be the next things I check.
 

NP2626

Well-Known Member
#13
My guess is the screw holding the trucks to the car are probably a little to tight. A permanent fix would be to sell the problem cars, if you just can't determine what is wrong with them.
 



ModelRailroadForums.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to amazon.com

Top