Constant derailments on my Peco code 83 turnouts

[selector]

Six axle diesels, even long ones, should have no trouble through a #5 or higher.  If they are derailing at the frog, it is often the case that what is happening behind that truck, way back down the frame, is where the real problem lies.  I found this out a number of times.  If the rear part of the frame is rolling or dipping, it may have the effect of rotating the frame too much forward and lifting one or more axles just enough on the leading truck that the flanges don't make contact with the inner face of the rail head.

I have many Code 83 Pecos, the #6 Insulfrog variety.  They all work 100% reliably.  If the frog flangeways are clear, if the guards are in spec according to the NMRA gauge, and the turnout itself is flat with reasonably tangential approaches/exits all meeting it at grade, I couldn't imagine that it's anything else but the locomotive.  But, if the turnout isn't properly suspended/supported along its entire length, both rails at the same height across from each other throughout, if the frog isn't high centered due to uneven support below it, or too low, or if the approaches in all three cases are highly curved, you can expect lots of headaches.

-Crandell

[Doughless]

What's the frog # of the turnouts?

Are the diesels 4 axle or 6 axle (3 axles per truck)?  6 axles and sharp, low numbered, frogs may be a problem.

Is the turnout laid flatly?  If laid with even a slight twist or bow to it, it can cause problems.

[steemtrayn]

Wheels in gauge? Some turnouts are more forgiving than others.

[popbagz]

Looking for help here. Just started testing my layout and am having trouble with my engines all (BLI deisels) derailing through the Peco code 83 turnouts. all other rolling stock does fine.Does anyone havve this problem? Any suggestions as to what I should try? Enginges derail as they reach the frog. This is happening on three different turnouts.