I think you will find the flanges are not contacting the bottom of the crossing moulding, Peco are pretty good at getting their mouldings right. (It takes a very coarse flange such as the old 'pizza cutter' flanges on Lima to foul on the bottom of the moulding.)
You have actually begun to identify the problem by seeing the 'balance' issue. The problem is that the point base has a slight upward bow imparted by the curved rails attempting to straighten - that's an issue Peco haven't corrected. What happens as a result is that the centre coupled wheel is raised slightly on the plastic crossing, and the loco balances with both of the coupled wheels either side out of contact with the rail - and there is no pick up!
If you take one of these points off the layout and sight along the rail top - which should be flat, i.e. horizontal - you will be able to see the upward bow. Comparison to a steel rule as a straightedge will make the slight deviation apparent. It's not gross, but it only needs a tiny airgap between tyre and rail to prevent current collection.
Cure. My preference is to glue down the point on the ply base.I have some steel blocks which sit on top for at least 24 hours as the glue goes off. (I do this on Peco live crossing points too, rail top should be horizontal, on all except intentional gradient transitions.)
Then again with the steel rule straightedge. If there is any hint of a rock across the crossing, use some fine abrasive paper on a small block to bring the plastic crossing down to match the metal rail top. Gently does it, there shouldn't be much to remove and avoid scratching the rail top.
You have actually begun to identify the problem by seeing the 'balance' issue. The problem is that the point base has a slight upward bow imparted by the curved rails attempting to straighten - that's an issue Peco haven't corrected. What happens as a result is that the centre coupled wheel is raised slightly on the plastic crossing, and the loco balances with both of the coupled wheels either side out of contact with the rail - and there is no pick up!
If you take one of these points off the layout and sight along the rail top - which should be flat, i.e. horizontal - you will be able to see the upward bow. Comparison to a steel rule as a straightedge will make the slight deviation apparent. It's not gross, but it only needs a tiny airgap between tyre and rail to prevent current collection.
Cure. My preference is to glue down the point on the ply base.I have some steel blocks which sit on top for at least 24 hours as the glue goes off. (I do this on Peco live crossing points too, rail top should be horizontal, on all except intentional gradient transitions.)
Then again with the steel rule straightedge. If there is any hint of a rock across the crossing, use some fine abrasive paper on a small block to bring the plastic crossing down to match the metal rail top. Gently does it, there shouldn't be much to remove and avoid scratching the rail top.
