Kato FEF-3 problem with front truck deraling, and rear of the loco bobbing

[peteski]

This discussion started as OT post in another thread. I think it deserves a separate discussion.

Quote from: carlso on April 17, 2020, 09:37:06 PM

KATO had a huge (I think) hit with their 4-8-4 #844. Am I sort of correct here?

I am not so sure. It looks good.

Mine has a weird problem. I can't figure out what to do.
The front truck (4) ist very lose. It jumps off the track quiet easily, which leads to derailments. I have no idea what to do. The beautiful 4-8-4 now sits on my shelf. 
   Javier

There should be a spring at the pivot point which exerts downward pressure on the front truck (keeping it on the rails).  It should also swivel easily slide to side.  But these locos have narrow tread and small flanges, so if your trackwork is not very good, they will have problems staying on track.  These locos (for the same reason) also do not like Peco switches: the drivers drop down into the frog's flangeways.

Is it always jumping the track at the same locations?  That might indicate problem with the track.

[peteski]

Thank you. I will check that.

The main point is: the spring seems to be quit weak, it doesn't have a lot of tension. Perhaps I should get another one from Kato.

And the truck swivels A LOT from side to side. IMHO too much. Could someting be broken?

Oh, there is another strange effect: The cab goes up and down like a ship in heavy sea when the loco is running. I've never seen a steam loco do that as much as this Kato loco.

   Javier

The front truck is strictly cosmetic (doesn't carry any weight), so weak pressure from the spring should be enough to keep it on the track.  It also needs to be floppy so it can follow the track.  I have to find mine to check, but I think floppy is good.

EDIT: I checked my model and yes, the truck is very floppy and the spring is very soft.  Also the truck is not symmetrical.

On the left in this photo is the front of the truck (with a tab in the center), and it should be pointing to the front of the loco. Check yours - maybe the truck somehow got rotated?

The up-and-down cab sounds strange. Since the loco is one solid object, if the cab bobs up and down, the front of the model should do the same, in opposite phase.  Do you see the front going up and down too?  I really don't know how to address that.  Can you take a video maybe?

Is this happening on a flat tangent track?!

[RBrodzinsky]

My GS4 has had a similar up/down bobble for its entire existence. You can see it here, starting at about 1:30. The cab not being properly seated actually makes it easier to see.

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[peteski]

My GS4 has had a similar up/down bobble for its entire existence. You can see it here, starting at about 1:30. The cab not being properly seated actually makes it easier to see.

But it is the whole locomotive (not just the cab) that is "limping".  The boiler is also bobbing. Like one of the drivers was messed up.  Did you ever get it to run smoothly?

[RBrodzinsky]

Nope, have had it for 10+ years, and it has always been like this. Kato took a look at it once, early on. All the drivers have been swapped, too. Seemed better immediately afterwards, but then it reappeared. It isn’t quite as noticeable in real life vs the video, but it is always fun to see who does and doesn’t notice at shows.

[ns737]

could it be slop in the frame or bearings or both

[carlso]

JAVIER,,
Did you purchase the FEF new?

Since Sir Pete did not mention problems with his pony truck derailing and causing problems and because mine has not done that either, I think there is something else causing that to happen. You mentioned that the cab bounces up/down when running and that should not happen. I feel that that "bounce" may be causing the smoke box end to, somehow, cause the truck to pop off rail.

I am attaching an image of how the cab end of the loco should look. You will note that the boiler shell is held down with a screw. Actually it appears that there is a "floor" with seats for the cab area.


Here is an image of the boiler shell sitting on table top, note the cab area has groove in the tongue for the screw.


I hope this has provided some food for thought,
Carl

[Mike Madonna]

My GS4 has had a similar up/down bobble for its entire existence. You can see it here, starting at about 1:30. The cab not being properly seated actually makes it easier to see.

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Rick,
Did the same install on the same exact loco! Sounds familiar 
Very pleased with the final product. Just wondering what values you used in CVs 2, 5 and 6?
Thanks!!

[RBrodzinsky]

Rick,
Did the same install on the same exact loco! Sounds familiar 
Very pleased with the final product. Just wondering what values you used in CVs 2, 5 and 6?
Thanks!!

I use the 28 step speed table, set linearly.  CV2=2 and CV5=222

[woodone]

Don’t know if any of you have had the driver cover retainer plate off.
On the GS-4 the bearings that fit into the frame are a PITA to get seated once removed.
I believe the replacement drivers come with a different bearing.
You can get one back together with the bearings not seated into the small groves .
Like I said there are a PITA because there is very little room for them to fit correctly.
Not sure on the FEF, I have not had mine apart.

[mmagliaro]

Don’t know if any of you have had the driver cover retainer plate off.
On the GS-4 the bearings that fit into the frame are a PITA to get seated once removed.
I believe the replacement drivers come with a different bearing.
You can get one back together with the bearings not seated into the small groves .
Like I said there are a PITA because there is very little room for them to fit correctly.
Not sure on the FEF, I have not had mine apart.

Okay, I'll get involved in this.  That GS-4 wobble looks quite like what happens when the bearings are not seated in the frame.
And when Rick mentioned that he got it repaired, and it came back and worked better right when he got it back, but then started wobbling again, the bearings were the first thing I thought of.   The thing is (as some of you know from my postings, threads, and repairs on this), on some of them, you really cannot get the bearings to stay in place in the new replacement GS-4 drivers.  There is simply not enough metal on the bearing "ears" to keep them seated. 

Here's the repair thread with photos on what happens.
If a bearing comes out, the engine can still run, but wobble like that.  Sometimes, it jams the rods.
https://www.therailwire.net/forum/index.php?topic=35367.0

None of this may apply to the FEF.  I do not own an FEF.

[ns737]

thats why I asked about the bearings I remembered your thread.

[randgust]

You've really got do get down and get in there close enough and with enough lighting to tell what is going on.    You may even need to set up a test track at eye level and put down some sectional curves to figure it out.

Truck tipping on curves?    Picking at rail joints?   Hanging coming out of curves?    I've also identified wheel profile as a culprit; if there's little or no fillet on the wheels and/or flanges aren't tapered much, hitting a curve will cause the lead outside wheel to simply climb off.  May have to change wheelset on the lead axle, although weight helps that one a lot.

Lead trucks on about any steam can make you crazy.   I know one standard approach I've done is add a little bit of lead weight on the front truck lead axle any place I can find to put it.   It's stabilized the performance of my Atlas 4-4-0, Jamco 4-6-2, Hallmark 4-8-4 .... none of which are particularly good trackers and all have given me fits at various times.   And yes, gauge is critical, but sometimes you create new problems if you correct the gauge as the wider wheelsets can hit things they never hit before.

The other thing that can happen on 4-wheel lead trucks is that as they swing around the cylinders they can come in contact with all manner of details, flanges rub on the cylinders, frame, or otherwise lock up and the wheels don't rotate as the inside wheel surface 'grabs' on the lead truck frame.

[Ngineer]

@All

Thank you very much for your responses and help. 

I will check all of your suggestions, but it'll take me some time.

I didn't know that the front truck was purely cosmetic. I thought it would steer the loco somehow through switches and curves.

   Javier

[peteski]

I didn't know that the front truck was purely cosmetic. I thought it would steer the loco somehow through switches and curves.

   Javier

That is its job in 1:1 locos, but I have never seen a functional leading truck in any N scale loco. They are all just along for the ride and to look pretty. Probably the same in H0.  Even thought N scale curves are much tighter than prototype, due to the laws of physics (and enormous size if N scale wheel flanges), they don't need to be functional.

They might be functional in larger scales like 0 or G?  And I'm pretty sure that the "live steam" model trains have functional leading (and trailing) trucks. But those weight hundreds of pounds, so they behave more like 1:1 trains.