#2 BLOG, premier gg1 and ef-3 b front truck jumping off of track and switches

post up some pictures of the problem areas. as much as you can, as close up as you can. set the offending locomotive right on the spot before the offense occurs. take pictures of that spot. we're shooting in the dark without an idea of whats going on....

Item numbers? Are the trucks lubed and greased to pivot/swivel easily? Is there a spring? Is it intact?

As mentioned above by HARMONYARDS, images help.

The first run of the MTH New Haven EF-3b locomotives (that I purchased about fifteen years ago) had tracking problems and had to be returned for repair. My two examples were serviced and ran well afterward, although I haven't run them recently. I seem to recall being told that the issue was improper wheel gauge.

MELGAR

I also have the MTH 5 volt NH EF3B.

It wobbled down the track.

The gauge of the powered wheels was too wide. I discovered this too late for MTH to repair under warranty—even though it was a chronic manufacturing defect.

I disassembled the power trucks and carefully squeezed the wheels together in a vice.

That cured my problem.

 For your front truck problem, I suggest removing the offending truck. Then check to see how it tracks through your track work. I suspect that the wheels are out of gauge. Then adjust the gauge or get new wheel sets from MTH.

Thanks for your help. I will take the trucks off both engines and possibly replace the wheels with original post-war Lionel ones. You think this is okay?

please don't take this wrong way, I just don't want to see you get frustrated like Ive seen a lot folks do. throwing parts at something (anything for that matter) is just a road to frustration. going through the work of swapping parts just to find out it didn't fix the problem gets old quick....before you go taking the trucks off, get your handy-dandy cell phone or digital camera...or a buddy with one and snap some pictures of what you got going on.....There is ALOT of good talented techs on here that can help you pinpoint the problem.....Diagnosis is key, not shotgun repairs....not trying offend anyone Id just hate to see the possibility of you getting frustrated and parking those two beautiful locos!!

Measure the distance between both flanges on the Vision line and compare to the locos that you have a problem with. If so make the adjustments and you should be good.

Much thanks for all your help. I am definitely getting frustrated but am also determined to get the issue solved.

I will try all your suggestions and see what happens. I know now that one area my gargraves o72 is smaller. I am going to make corrections to that. I also noticed that coming into a straight on one Ross which seems to have problems with both engines that is the straight side of the switch. I am also going to look where I have had problems as you suggested and try to repair that area one at a time. Fortunately there is only a few areas that I'm having problems with. 

Thanks again you all, Jerry