inferior truck design?

What does this have to do with TMCC or Legacy.  The issues you are describing would occur just as often with convention operation.  If you have an issue with the the operatioal aspects of the way the trucks are being mounted to the frame I'd stay away from engines that use that mount.

 Well, should I order new onew and see if they're still mounted off center and will tip up and off the rails?

Contact Lionel Service by email or visit a local hobby shop before you order any more equipment and wind up with the same issues.  There have been a lot of design changes to make the equipment easier to service/replace or to cut down the part number/assembly process.  I only have a older 3 axle truck loco's with vertical can motors and those have the motor mounted near the center of the truck.

 It's where the truck pivot mounts to the frame that's off center. I will go to a hobby shop, that's a good idea.

Joe,

I'm lost, re: the problem you're trying to show???

BTW, that CSX unit does not look like an EMD SD70MAC... where's the, front and rear, AC traction equipment, venting, on the long hood?

At best, you've got something that resembles a DC traction equipped - SD70M.

Just kidding, but it's kind of amusing caring about fixed pilots etc. and then not having the correct AC traction features present; besides, the added length of a SD70MAC, they're 20" longer than their DC counterparts(SD70M's are 72'4" and SD70MAC's are 74'0"); the AC traction venting is it's most distinguishing feature.

Rick

Once your CSX model is sitting on the rails, and moving forward - the added length and weight and the offset pivot point should work in it's favor, producing greater traction; the front truck would have the opposite effect, when moving forward, with the shorter part(re: the pivot point) leading the way.

Rick

I believe the purpose of this is to reduce the outward overhang of a long loco on curves. If all axles are powered and all wheels contacting the rail, it shouldn't be a significant factor in reducing traction because the entire loco weight is still on all the drivers.

 Oops, this post got moved and I just stumbled across it. The trucks actually tip when the engine's under load. They tip up towards the frame near the fuel tanks on the inboard axle the most. The screws help so I thought I would adjust them out a tad. That doesn't allow for bumps in the layout and causes the wheels to come off the track. So I put them back in to where they were. I would design some spring pushers but seems like too much work. All axles are not seeing the engines weight evenly.

 "Stay away from these engines" maybe good advice if I knew which Lionel six axles are like this. Are the new ones built like this? I maybe asking too much to convert something like this to two rail. That may scare me away from the others like the SD70 Kline/Lionel that I wanted.

 The CSX engine is a custom and I forget what the exact model was, but if you check the CSX roster, I see some custom units with flared radiators that this represents. Close enough for me.

 I'm having issues with the TMCC getting along with my DCS signal on two rail anyways so abandoning these may be the best move. Seems like I can get either signal strong but not both at the same time on the same rails.

 The pilots must be fixed if you think about running and backing long trains on two rail track. I believe he just modified whatever model Lionel had around at the time. I'm pretty happy with it representing a CSX with flared radiators. I think it will become a dummy.

 The axles aren't contacting the rails evenly. The whole truck tips.

 This sounds impressive however it doesn't happen that way. I'm not even sure what you're describing about extra??? When trucks wobble on the track they lose traction. The wobble is the truck trying to gain traction, it can't because every time it does the whole truck tips and slips. The weight is not applied evenly to the axles.

 I guess it's something you'd just have to witness in two rail to see the problem. I will try and shoot a video if I can capture the actual problem while it occurs.

Joe,

I should have identified the rear truck, as the truck I was referring to, initially.

The front truck should have the same benefit, when reversing; but, only one truck, at a time, would benefit from the leverage gained from the offset pivot point. The opposing truck would probably be at a disadvantage, due to the short side of the pivot point wheels leading... Basically, both sides, the front and rear trucks, are working against each other.

Just my theory.

Rick

BTW, my theory is based on the inner axles wheels(front and rear) closest to the fuel tank being flanged and powered. If those axles and wheels are just free floating fakes, disregard my posts.

Rick

 Yeap, the replacement two rail wheels are all flanged. The trucks do fight themselves and each other. A simple lap around and one of them usually derails. This has stalled my thoughts on two railing Lionel's in the future. I'm sure this has been done. So, I want to know what do these trucks do with three rail track? Obviously not as big a problem?

 I have it posted on the two rail forum and wonder what other two railers notice?

Where do the trucks derail? Is it on curves or straights, changes in grade, pointwork etc.?

Joe,

You aren't the first to notice how the truck mounting system and the torques involved can affect tractive effort. Years ago in Model Railroader magazine, John Armstrong described a similar situation with the trucks of the old Atlas 2-rail F9 diesels. He solved the problem by changing the truck mounting system to reduce twisting motions that were reducing tractive effort.

His job was made a little easier since much of the frame and truck assemblies were plastic and the horizontal drive system was more easily modified.

So at least your observations put you in good company with one of the most famous mechanical engineers ever involved with model railroading.

Jim

 Must be an accident!!!! Wow, thanks Jim!

Unfortunately Nicole, I can't pin down where exactly they derail. It seems it's more a question of when. The trucks shudder and jump a bit. I was thinking of spring loading a mechanism to keep the trucks level?