There is a difference in rail joiners between Peco and Atlas, and the Peco rail has a narrower foot in addition to having a slighlty thicker crosstie.
When I built my home layout using Peco code 83 flextrack I tried to also use Peco turnouts as much as possible, but had to use a couple of Atlas crossovers and turnouts where Pecos wouldn't fit.
A Peco rail joiner won't fit onto Atlas rail, and an Atlas rail joiner fits losely on Peco track and has to be slightly squeezed to fit tightly.
I was forced to use one Shinohara code 83 turnout, too, but don't remember if there was a problem getting it to marry up to the Peco flextrack.
"The true sign of intelligence is not knowledge but imagination."-Albert Einstein
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I have used Peco Code 100 turnouts and Atlas Code 100 flex track on my first layout a few years back. When I used Peco Code 100 turnouts with Atlas Code 100 flex track on that earlier layout, I did not have to do any shimming at the joints between the Peco Code 100 turnouts and the Atlas Code 100 flex track
Now I am working on a smaller new modular layout and I am considering using the new Peco Code 83 turnouts with the Atlas Code 83 flex track. From the modelers on this board that might have used the new Peco Code 83 turnouts with the Atlas Code 83 flex track, are we still good with not having to shim the joints between the Peco Code 83 turnouts and the Atlas Code 83 flex track?
I would appreciate responses from those who have recently used these Peco code 83 turnouts with Atlas Code 83 flex track. Thanks for your expertise.