Jumping truck

[upnick]

Hi guys,

After running my Athearn N big boy here the truck under the cab jumps the rails in one place i have checked the track and its faultless ... have any of you had this and how did you solve it ?

[nachoman]

If it is one locomotive having problems - more than likely it is a wheelset out of gauge. Get an NMRA gauge and check. If it turns out the wheels are in gauge, then check the gauge of the track at that spot. Is this spot of track on a curve, near a rail joint, on a grade, or near a switch?

Most of my derailments can be traced to wheelsets out of gauge. In the past I have had problems with putting too sharp of curves on grades or abrupt transitions that caused some trackability problems.

[upnick]

Hi Kevin,

Thanks for the advice it is on a curve ...... i'll try your suggetions

[yellowlynn]

If it is the trailing trucks (not drivers), sometimes they are too light in weight and will jump easily. It just might be that circumstances are just right to "bounce" at that spot.

Lynn

[poliss]

Are you using flexitrack Nick?

[upnick]

Are you using flexitrack Nick?

Hi Poliss,

Yes i am using flexitrack code 55 does it make a difference ?

[eightyeightfan1]

Is the track ballasted?
Might be a piece of ballast, stuck to the inside of the rail. With the light weight of the trailing truck, that one small piece maybe bouncing the truck out.
I've gone crazy(even in HO) trying to figure out why one car would derail, and another won't. Went nuts looking for the problem, til I ran a small screwdriver along the inside rail, and knoked loose a piece of ballest that was stuck.
No problem since.

[poliss]

I have read that when bending flexitrack that it can go slightly out of gauge which may be the cause of derailments. I would run a bogie over the curve and see if there's any narrowing of the track.

[Herc Driver]

I've had that very experience of bending flex track and getting a ever-so-slight out of gauged section. Not even perceptible to the eye, but would cause a derailment of very light weight cars, or the rear wheel sets of my J-Class 4-8-4. I just assumed I didn't do a good enough job of laying down the flex track, removed the entire piece and installed snap track. That solved my problem.

Nowadays, I try to run a passenger car over all the track to hunt for problem track areas. You can really feel the car slow down and bind up when it traverses a bad section of track that might be out of gauge, or too tight a radius.

[upnick]

Hi All,

Poliss ........ i tried a truck over the track and everything is fine also ran a gauge over it and that was ok.

88 ........ the track isnt ballasted yet but is just on the exit of the tunnel on the upper level ... i ran a dental pick over the rails and gave it a good vac out tested her and alls well

No idea what it was but solved it now .... its not the first time i have heard the truck under the cab jumps.

Many thanks guys

[poliss]

A lot of searching finds very little info about the problem Nick. The one result that keeps coming up in searches is an old post of mine when I first got it. :-) According to me the problem might have been because the front truck was sprung, but I found out that it was actually a loose fishplate that caused the problem. Funny how easy it is to forget things.

[upnick]

Hi Poliss,

Yes the mysteries of railroading can confuse at times i thought of using a fishtank plant wieght on top of the truck possibly as long as it didnt foul the truck/loco underside but she runs well now over that section of track.