Update:

I won't say the problem is "fixed" yet - still a lot of testing "miles" to verify, but I does seem to be OK now...

I looked at all my other EZ-Track #4 turnouts, and found that all of them had a slight (but visible) curve in the switch point for the divergent route - I proceeded to CAREFULLY put a similar bend in the point on the problem turnout...

I did some "bench testing" and spotted another problem with this turnout. The metal frog installation had multiple problems.
1) The frog was "high" and not level with the track leading up to it or departing from it. This would be one source of the "clunk" sound, as the truck wheels would potentially hit the edge of the frog on approach and drop off the trailing edge as they pass over it...
2) The molded plastic around the (metal) frog made the above problem worse as it seemed to have expanded out in such a way as to both stick up above the rails in the gap between the rail and frog, and it also had pushed out to the side of the frog/rail junction, creating an obstacle for the wheel's "lip"...

I again CAREFULLY worked on the frog, filing the top down to be level with the rails, and then used an exacto knife to clean up the plastic so that it was smooth and flush with the rails, but not sticking out...

NOW the turnout seems to "work", and initial testing with two SD40's and an old blue box SD9 have been successful....

After more extensive testing, I will try to post how it is doing....

Just an additional note: The NMRA gauge will NOT fit through the pinch point in the switch... the tight spot created by the straight point -vs- the curved rail is roughly 1mm too narrow for the gauge...

I have found out the hard way that my EZ-Track #4 turnouts have a problem... The point for the curved route is straight (no curve in it at all)... B-B engines seem to be able to work OK, but C-C engines do not.

The problem is that the corresponding rail IS curved, and with the point being straight, this creates a "pinch point" in the middle of the turnout... This causes engines such as my SD40-2 to derail almost every time - even when the engine does not derail, there is an audible "clunk" as the wheels ride up on the pinch point, then drop back down...

The most obvious "solution" would appear to be to BEND the switch point to match the curve in the corresponding rail... However, initial attempts seem to risk damage to the switch. the tip of the point is only a friction fit into the plastic bar that moves the points and the opposite end is just riveted to a contact... Forcing a bend in the point risks either breaking the bar or the rivet attaching point...?

Has anyone else had this problem...?
How did you solve it..?

First - THANKS for the responses... Let me respond...

I have an NMRA gauge, and checked the engine's wheel spacing - all were within spec...

So - I did a close-up inspection of the switch... Since this section of the layout does not have the EZ Track glued down yet, I was able to temporarily remove the switch and take it to the workbench... Nothing was actually "binding', but the points did not move as freely as I thought they should - this contributed to a less than "clean" closing of the points. I took the time to follow the posted advice and gently tweaked the points to ensure that they could close completely and that any burrs or sharp edges were removed from the tips of the points. At this time I also noticed that the plastic "bar" that connects the points seemed to rub/bind slightly where it moved under the rails, so I lightly "shaved" a tiny bit off the top surface to ensure ease of motion. Then I noticed that the "pin" that sticks up through the plastic roadbed to allow manual movement of the switch points seemed to "hit" the end of the slot in which it moves a bit too soon when the points were moved in one direction - I found some "mold lines", etc. and used an X-acto knife to shave the end of the slot to allow the full range of motion...

I re installed the switch and tested...

The problem seems to be resolved... I will do some more testing, but the engine made several passes over the "fixed" switch with no issues of any kind...

Thanks again for your input...

I just bought a new B23/B30-7 engine, and it seems to "pick" the points on one particular turnout... It never does this on any of the other turnouts (all track is Bachmann EZ-Track)... But 9 out of 10 times, it will de-rail on this one turnout...

No other locos have an issue with the turnout (Athearn Blue Box, Atlas yellow box, Atlas Classic/Silver, even other Bachmann engines...)

So.... Ideas?

I have checked track joints, the turnout points feel smoooooth... I'm lost on this one...?