Low hanging truck frames on Intermountain FT's

[Bendtracker1]

With the Recent announcement of the KATO F2's in the Rock Island red and black schemes, I decided to pick up a pair to go along with my IMRC FT's and F7's in that scheme.
The other night I got my first pair of FT's chipped and running, then got one of the F7's chipped and running.  I got them speed matched and when I tried to run them as a three unit set, the first turnout that they ran across, the FTA bobbled a bit, the FTB derailed and the F7 made it through OK.

At first I thought the wheels might have been out of gauge, but closer inspection showed all the trucks frames on both the FTA and FTB were riding on the rail head!  One of the FTB frames was actually hanging a bit below the rail head.

I jumped on the computer and did a Google search for N Scale IMRC FT Trucks and ran across an older post here on TrainBoard about someone asking how they ran and if they are worth the money.

One poster mentioned that he was very happy with them and only found one problem and that was that the truck frames on all of his FT's were hanging too low and rubbing on the rail head and would derail.  He went on to say that it is was and easy fix, all he had to do was "Re-Snap" the truck frames back into place.

Post #5
http://www.trainboard.com/grapevine/showthread.php?134823-Intermountain-FT&p=807369#post807369

Other than this post, I cannot find anything else about anyone having troubles with FT trucks.

I went back down to the laboratory this afternoon to take a closer look.  I came up empty handed.  As far as I could tell, the frames are snapped into place securely, but they do seem kind of loose.  Not sure what else to do?


So....I decided to see if I could stir up anything here?

Has anyone have/had this problem with their FT's and have you come across a fix?

[johnh35]

Does IM use the Atlas GP trucks with different sideframes on the FT?

[Bendtracker1]

I think they are different, but it's worth a closer look.

[Bangorboy]

This is from a while back.  I got an ABBA set of IM FTs when they first came out.  They were from an early run which had the motor wires hard soldered to the light board.  I see people are finding this arrangement on some that are recently purchased as well.

But back on subject:  I found three or four trucks on these four diesels that would derail easily and showed drag marks on the bottom surface.  Turned out the frames were on tight enough to stay, but were not fully snapped into place on all latches.  This caused them to hang low enough to drag.  Pressing them fully into place fixed the problem.

[spookshow]

But back on subject:  I found three or four trucks on these four diesels that would derail easily and showed drag marks on the bottom surface.  Turned out the frames were on tight enough to stay, but were not fully snapped into place on all latches.  This caused them to hang low enough to drag.  Pressing them fully into place fixed the problem.

Yep, been there done that. The trucks on mine got similarly discombobulated when using them as grip points while trying to finagle the shell off 

Cheers,
-Mark

[sizemore]

Pull the sideframes off and look for molding flash on the inside of the sideframes between the wheels (front to back). The most recent release of GP7/9's from Atlas has this same exact problem. Clean the flash and pop it back together.

The S.

[Cajonpassfan]

Well, I've had two ABBA freight sets running on and off for several years, and now the "dragging truck frames" problem has raised its ugly head. As much as I have tried to "snap" the sideframes back in their place,  no luck; every time I cross a turnout, they drag... I even tried to sand off the bottoms a bit, no joy.
What's the fix, anyone? Buy new units just for the trucks? That seems a bit over the top (and expensive)
Thoughts, anyone?
Otto K

[mark.hinds]

I bought a pair years ago, but never ran them.  So after reading your post, I took one apart. 

On mine, the truck bottom plate is cast with the side frames.  This snaps on to an inner plastic box holding the axles and gears, using 4 corner clips.  The axles are apparently held in place by a brass end cups on a T-shaped brass arm, attached to the inner plastic box.  The axles are held fairly loosely, so that I can move any particular wheel up and down with my finger, and this “slop” may be by design, to allow some gear position adjustment.  Even when firmly snapped in place, the bottom plate is positioned in such a way that the cast wheel bearing housings (or whatever they're called) are low relative to the axles, when viewed from the side.  So if a particular wheel / axle end was even a bit high, the tire of the wheel might be too close to the bottom plate. 

If I have to deal with this issue on mine, I think I'll try to fix a particular wheel / axle end by bending the brass arm “down” slightly towards the truck bottom plate.  If done properly, this would still leave some slop in the mechanism.  The tricky part will be to do this without distorting the arm out of its original plane. 

Mark H. 

[peteski]

Could this problem be caused by the pointy ends of the axles not protruding far enough out of the wheels. If they are too short they will ride in the upper part of the bearing cups (instead of in the center).  That would make the truck sideframes look like they droop. 

[drgw0579]

I was looking at a set of these trucks and sure enough one of mine had the same problem.  I tried snapping it back together, but the axle wipers weren't positioned correctly. The probably happened when I tried to pull the trucks off the frame.  I found it was real hard getting everything back the way it suppose to be without bending anything, but finally I did.  The truck frames don't seem to clear the rail by much anyway, so even a slight mis-alignment could cause problems.

Bill Kepner

[Cajonpassfan]

Well Bill, thanks, I will try to play with it this weekend.
Interesting idea Pete, these units have a lot of miles on them and if the wear on either the cups or axles makes the points ride too high, that would drop the sideframes just enough to drag. Hmmm.... I need to find time to study this, but frankly, I'd rather do other things like work on the layout than dick around with dragging sideframes...but I would like to get these pups back in service:

Meanwhile, over the weekend, I also sent a request to Intermountain parts department to see about replacement parts, but so far, no response.
Otto K.

[peteski]

Interesting idea Pete, these units have a lot of miles on them and if the wear on either the cups or axles makes the points ride too high, that would drop the sideframes just enough to drag. Hmmm.... I need to find time to study this, but frankly, I'd rather do other things like work on the layout than dick around with dragging sideframes...but I would like to get these pups back in service:

I have a set of these from the initial run and they don't have much mileage on them. But They have been put away and I would have to spend some time to find and dig them out to see if they already have that problem with low hanging truck frames.   That's not happening anytime soon.

While worn bearing cups could result in what I described I think that the axles were too short coming right out of the factory.   In that case worn bearing cups would have only made the problem worse.

[mark.hinds]

(text removed)

While worn bearing cups could result in what I described I think that the axles were too short coming right out of the factory.   In that case worn bearing cups would have only made the problem worse.

If in fact the problem is "short axles" or "worn bearing "cups, wouldn't merely bending the brass arms in a bit tighten things up again?  Note that your theory is an alternative to mine that the "slop" was intentional, though you could be right. 

MH

[peteski]

If in fact the problem is "short axles" or "worn bearing "cups, wouldn't merely bending the brass arms in a bit tighten things up again?  Note that your theory is an alternative to mine that the "slop" was intentional, though you could be right. 

If this in fact was the problem (axle ends should protrude further out) then I would take the wheelsets apart and push the half-axles out. Like a reverse of what is shown in this drawing.



KatoWheelset.png

[mark.hinds]

If it is what you surmise, Peteski, then one could identify the condition by inverting the truck, pushing down on each wheel with a finger, and seeing if they all show the same clearance from the bottom plate. 

If both wheels on each axle show the same clearance, and it is inadequate, then one would presumably either extend the length of the axle per your diagram, or push in (out of plane) the brass cup arms slightly. 

On the other hand, if both wheels on each axle show different clearances, then I would go with my original suggestion above, and bend the brass cup arm for the low wheel, slightly, in plane.  This latter is what I saw on my FTs.

MH