Some RealTrax sections have a misalignment problem with the rails at the joints. There could be a mis-match on the outer curved rail that could cause the flange to climb the rail. Does it derail in the opposite direction? If not, then I would check the joints carefully. Also check to see if the traction tires are smooth, without any bumps on them caused by foreign material lodged under the tire. It can cause the driver to lift slightly, but I would think you would notice a wobble.
As for the pickups, lay the loco and tender on its side or in a cradle and see if it will power up with one lead on a pickup roller and one driver. Let it power down, then check the other roller and one driver. If both work, then check one roller and each driver separately. Also check the tender wheels as the PS2 harness likely has a ground in the tender. See where the loco is picking up the ground connection (outside rails) to determine if there is a sufficient ground.
