Derailment woes

[bearman]

How is it that you can have a layout that has been running reasonably smoothly, and then all of a sudden one particular locomotive, out of four, starts to derail at the same location and only when it is going in a particular direction.  There is a rail joiner and it looks like it is derailing as the wheel flange passes over it, so I get out a file and file down the part of the joiner which may be contacting the flange.  Then I make sure all ballast around the joiner is scraped off the top of the ties and run an exacto blade along the inside of the rail before and after the joiner to make sure there is no foreign particles there and it still derails.

[richhotrain]

bearman

How is it that you can have a layout that has been running reasonably smoothly, and then all of a sudden one particular locomotive, out of four, starts to derail at the same location and only when it is going in a particular direction.   

I have been experiencing a bit of this lately as well.

Let me ask you this.

Has the locomotive performed flawlessly in the past and now just started experiencing problems?

Have you recently done track work?

What type of locomotive?

Rich

 

[richhotrain]

deleted

[bearman]

Yes, a plain derailment not a stall.  Usually a stall indicates dirty track, which is easily fixed.  The circuit breaker has not indicated a short and the locomotive, a Walthers GP9, #2092, has performed flawlessly in the past.  The track on this portion of the layout was laid and ballasted months ago.  

Have not done any track work on this portion of the layout since then, other than cleaning the black gunk when the need arises.  This portion of the layout is also easily accessible, the track is about 3-4 inches from the edge of the layout.  Usually, stalls occur due to black crud in those portions of the layout which require a bit of a reach.  And I just finished cleaning the entire layout.

Are there gremlins around? 

[richhotrain]

Bear, before your reply was posted, I re-read your initial post and then edited my own reply. I had raised the issue of stall versus short, but then upon re-reading saw that you indicated a derailment.

So, no recent track work, and the locomotive had performed flawlessly in the past.

The GP9 is a four axle diesel, the least susceptible locomotive to derailments compared to six axle diesels and steam locomotives.

Rich

[bearman]

I edited my initial response to identify the locomotive, Walthers GP9, #2092.

[BRAKIE]

I would break out the NMRA gauge and check things since it could be one wheel is slightly out of gauge and the joint is slightly out of gauge causing the headache..

[richhotrain]

bearman

I edited my initial response to identify the locomotive, Walthers GP9, #2092.

 

LOL

We are typing and editing simultaneously.

I saw your GP9 edit.

I am in agreement with Larry that a wheelset may be out of gauge. Does the loco derail every time over that same spot, or just occasionally?

Rich

[bearman]

I'll break out the gauge but I am not optimistic.  Here is how I trouble shooted the problem.  Ranthe loco from west to east over the joiner and the front wheel derailed.  After filing and scraping I ran it in reverse, east to west, over the joiner, no problem.  Then I switched the direction of the loco and ran it forward east to west over the joiner and no problem.  Running it in reverse, west to east, and there is a derailment.

[bearman]

Every time, Rich, and the problem started two days ago.

[bearman]

It seems to me if the wheels are out of gauge or the track is out of gauge then the derailment would occur in either direction.  The last thing I want to do is tear up the track in question and re-lay it.  The thought chills my spine.

[mbinsewi]

If I can jump in here,  just something I do to fix problems, can you get your eyes right down on the locos trucks as it passes through this area, while running the loco as slow as possible, and watch to see what is happening?

Mike.

 

[bearman]

Mike, I have done that from the side but I did not run the loco as slow as possible, I ran it at speed #5, but it will run at a lower speed so I will try that out.

[rrinker]

 Also sight along the rail, or run a fingernail over the joint - could be that the two piece of rail are not lined up, slight side to side offset can cause a derailment going one direction but not the other. Vertical mismatch can too but it would have to be much greater to have the same effect. Inside edge is where it matters, the outsides can be offset and nothing will happen, so long as the inside lines up.

 It's not very likely a 'modern' model with proper flanges would strike a rail joiner, unless the joiner is really bent up, which means it will not be holding the rails in horizontal alignment.

                    --Randy

 

[mlehman]

Depending on their cause, derailments from gauge problems can occur only in one direction. You mentioned a joiner, so I'm guessing the issue is where the rails meet with it? Is the transition from one rail to another all in gauge smoothly? Perhaps one rail is a bit tight or loose, causing the edge of the rail to protrude? This may allow the wheels to roll past in one direction, but be just enough bump to cause issues in the other.

[bearman]

Randy, I have done the finger test and everything looks ok from that perspective, although I will break out the gauge and fiddle with the joint a little later on.  I filed the joiner because that looked like the obvious problem but now I am not so sure.  The alignment both vertically and horizontally appear to be fine, and it is a nice tight joint.

Mike, the joint is not loose, I am sure of that.  And it is only happening with one particular locomotive.

 

Having typed all this I will, in fact, take the suggestions that I have not yet implemented to check out that joint.

[rrinker]

 Check the loco and make sure one of the wheels doesn't have a chunk missing out of it. Wouldn't be the first time.

                               --Randy

[BRAKIE]

bearman

It seems to me if the wheels are out of gauge or the track is out of gauge then the derailment would occur in either direction.  The last thing I want to do is tear up the track in question and re-lay it.  The thought chills my spine.

 

While that is true 99% of the time there is that 1% that is caused by a slightly out of gauge wheel and a slightly out of gauge rail joint. Been there several times over the years and its always a pain and can lead to this:.

Also recall 99% of the time our equipment is most forgiving over less then perfect track..

If the joint is slightly out of gauge there is no need to rip out the track. I simply use HO spikes (not track nails) and spike it back in gauge. That's a old school trick that still works quite well.

[richhotrain]

bearman

I'll break out the gauge but I am not optimistic.  Here is how I trouble shooted the problem.  Ranthe loco from west to east over the joiner and the front wheel derailed.  After filing and scraping I ran it in reverse, east to west, over the joiner, no problem.  Then I switched the direction of the loco and ran it forward east to west over the joiner and no problem.  Running it in reverse, west to east, and there is a derailment.

 

OK, this is a good troubleshooting analysis.

I drew up a crude drawing for myself, "running" the loco all four ways that you described. 

One question that I have is, which truck derailed, the lead truck or the trailing truck?

Since the loco is only derailing west to east, it seems that the loco is not the problem but rather the track is the problem.

I assume that it would be somewhat of a problem for you to remove the rail joiner.

When the loco derails, is the track right under the derailment a turnout? A straight piece of track?  A curve?

Rich

[bearman]

Good questions, Rich.  It is always the front "right" wheel on the lead truck on a curve.  I'll have to check on the rest of them  I'll probably print out this entire thread when I get back later on and have some time to deal with the suggestions that I have not checked yet. Believe me, removing the joiner is not an option.  To do that it would be easier and just as messy to tear up the track and re-lay it. 

[bearman]

And now, sports fans, things are getting grimmer.  I cant find my gauge which means a trip to the local model RR store which is 15 miles away and is closed Sunday through Tuesday, it used to be closer and open 7 days.  There is a hobby store a lot closer but their RR section is getting to be a lot more limited ever since the old-timer who ran the section retired 3 years ago.  If he was still around I would be pouring out my troubles to him.  He was always great with advice, just like all of you.

Feel free to have a laugh at my expense.

[richhotrain]

Forget the NMRA gauge. Others will differ with me, but I just don't find it useful.

[richhotrain]

bearman

Good questions, Rich.  It is always the front "right" wheel on the lead truck on a curve. 

So, always on a curve, always on the same spot on the curve.

Always on the front right wheel on the lead truck. By that, you mean, physically, the same wheel no matter the direction traveled and no matter which way the loco is traveling?

Or, do you mean, the right front wheel as the loco travels, which would mean the left wheel on the on the rear wheelset of the trailing truck when travelling backwards from west to east?

Rich

[bearman]

I have to get some couplers anyways and was delaying until I was in that part of town for other reasons.  So there will be a special trip on Wed.  I'll get the gauge if things dont work out today or tomorrow, if only to eliminate ALL possible problems.

[bearman]

Rich

First question...Yes.

Second question...No

Third question...Yes  (I guess I was not clear enough)

[bearman]

And now, I have another question about this situation which Rich's most recent post just sparked.  If there is a problem with the horizontal rail alignment which cannot be "measured" would I create a bigger problem if I filed along the inside of the rail in an attempt to get rid of any "lip" thereon?

[richhotrain]

OK, so as soon as the loco hits that spot on the curve, traveling west to east, the loco derails.

That would eliminate an out of gauge wheelset.

It is either the rail joiner itself or a kink in the rails where they connect on the curve.

Why now?  Could be temperature change, humidity change, expansion/contraction, who knows.  Happens to me, happens to others.

Why only that loco? Could be the measure of tightness of the trucks, lateral sway, again, who knows.

But when this happens to me with only one loco, fixing the track work is the cure.

You aren't going to want to hear this, but remove and replace the rail joiner. And solder the new rail joiner to the rails to remove any possibility of a kink.

Rich

[richhotrain]

bearman

And now, I have another question about this situation which Rich's most recent post just sparked.  If there is a problem with the horizontal rail alignment which cannot be "measured" would I create a bigger problem if I filed along the inside of the rail in an attempt to get rid of any "lip" thereon?

 

Filing rarely works for me in a situation like this.

If it were me, I would remove the rail joiner, put in a new rail joiner and solder it in place to remove any possibility of a kink.

Rich

[bearman]

You are correct, Rich.  I dont want to hear.  I dont want to read it.  And I am going to do everything that I can to avoid it.  But if I cant avoid it, I cant avoid it, and it will have to be fixed by tearing up and replacing the track.

Oh, happy days are here again!

 

[richhotrain]

To be entirely pessimistic, I cannot see fixing the problem without replacing the rail joiner (both rail joiners, in fact) and, for good measure, soldering the rail joiner into place since the rail joint is on a curve.  

Rich