Hi CPBuff, good points from Dave. Are your Budds Walthers cars? Did you redistribute the weight?
"I like my Pullman Standards & Budds in Stainless Steel flavors, thank you!"
Thanks Dave! I do have the weight spread out along the car! I'II move them so they are more centered over the axles!. Also the derailment point is half way down the grade but on a gradual curve!. NO track joints in the area, I will recheck the track again as well! Thanks for all the great information!
The problem is likely not the weight, indeed the usual response to tracking problems is to add more. Of course if the weight is too high, or imbalanced between the two ends, or is not significantly over the trucks, that can cause issues but it is the placement of the weight, not its poundage to so speak, that is at fault.
Without seeing the track and situation myself it is hard to dignose but the following occur to me.
1. Coupler mountings -- are they mounted to the body or are they mounted onto the trucks. Weight from behind would tend to skew the trucks if the coupler is mounted to them. It is not always practical to body mount couplers on full length passenger cars, but that is optimal if you have the broad curves that can handle them.
2. "Verticle easement curves." There needs to be a transition between a grade and the pure horizontal flat. If they meet at an abrupt sharp angle that is an invitation to derailment. Let me give an example. If you took a 4' long piece of plywood and nailed one end to the benchwork tabletop, and raised the other end to equal a 2 degree rise, there would be a smooth and even easement between flat and the rise. If you had two pieces of plywood and nailed one flat to the table and the other was at a 2 degree rise, there would be a sudden and abrupt change at the point there the two pieces intersect. Almost impossible for trains to negotiate. The more a vertical easement curve you have, the better the tracking
3. The curve at the bottom of the hill. Just as placing a turnout on a grade can be an invite to detailment, so can placing a curve right at the bottom of a grade be a problem as you are placing the centers of gravity at various stresses. A lack of a horizontal easement curve at that curve can also be a problem
4. Other track laying issues. I'd look long and hard at the track at the spot where the problems occur. Is it perfect even or does it favor one side or the other? Even placing a joint between two pieces of track at the wrong spot can cause an issue. You say you had no problems with the same cars on a similar grade on a prior layout. That would make me focus on the quality of the tracklaying rather than on the weight of the cars. It so easy to introduce a point of wobble. For example sometimes cork roadbed has an irregular surface which is why sanding it with one of those foam sanding blocks before tracklaying is always advised. Take two of the trouble some cars and very slowly hand push them down that grade with your head as close to the derailment point as possible, chin on the layout if need be. I'd wager that there will be movement of some sort at the spot. Maybe you'd even feel it with your finger if you slowly pushed a flatcar over the spot with your finger solidly in the middle of the flatcar's deck.
Dave Nelson
I'm having a problem I suspect is the weight in my passenger cars! When my 6 budd cars are rolling down the grade , the weight of the cars behind seem to push the cars up front (usually the closest to the loco) off the track. I did check the weight as per NMRA standards but it seems a bit excessive to me? 11 1/2" X .5 oz plus 1 oz.= 6.75 oz per car!
The down grade is less steep on this layout then on my last layout with the same cars!
How much weight do you add to your passenger cars?