Disappointed

[DaveS]

Perhaps the problem is the track. I built a small 4x8 layout using Trutrack. I experienced some derail problems with one loco going into an 18" radius curve. It is a light mountain and I know some of you will deride my using such a loco on 18" track but it is designed to take such curves. It is my largest loco and yes my Consolidation looks more the correct size but I like the light mountain and after all it is my railway no matter what CN has to say. I do have 22" on the main loop.  I had electical problems with the turnouts when I converted to DCC but they and all my track issues went away when I changed all of the track to Kato Unitrack. It is a far superior product. The problem I found with Trutrack is that you can't eliminate gaps at the rail joiners. Also the turnouts are poorly made. No such issues with Unitrack.
I have noted comments in this thread and many others criticizing the 4x8 layout. I agree there are limitations but saying you should go around the walls instead, as it uses no greater footprint, assumes the access aisles beside the 4x8 have no other use but board access. That isn't always true.
In my case my layout is in a 600 S.F. room but  the access aisle on one side is also the access to a large bookcase. On the other it is the "pathway" to the furnace room and also to my wife's harpsicord so a board is the only option. Quite frankly I was lucky to get that space as the CEO didn't have a model railway in mind when we remodelled the room a couple of years ago.

[danmerkel]

Check the gauge; remove any springs you can. 
Gene

Just curious... why would you remove the spring but then add weight to the truck???

dlm

[Atlantic Central]

Dan,

Physics 101

Springs are like levers, they exert equal but opposite forces at each end. That means a spring pushing a pilot truck down is also trying to lift up the frame of the loco transfering weight off the drivers and on to the pilot truck (or some where else).

Extra weight on the pilot truck is only effected by gravity so the only force is gravity pulling it down harder because it has more mass. The weight on the drivers is not effected like it is with a spring. More weight/mass on the pilot truck will reduce the amount bounce when it hits a rough spot.

Smooth track and large enough curves is still the real cure here.

Sheldon