It is the same height and gauge so they work together in that sense. They have different radii in the set track though so do not if making an oval with atlas for one curve and hornby for another.
Hornby and Peco are completely interchangeable with Peco using the same radii with the bonus of Peco being a much better product (and better than Atlas too) so if you need track look at this brand.
Hi all,
On my layout I have a mixture of Peco Flex and now set track which is identically profiled to Hornby, a length of Roco and Atlas track and there is only a slight profile difference when it comes to the rail joiners/fishplates... in short, go for it!!!
Cheers from Australia
Trevor
This is about Hornby vs. Peco
https://jonscaife.com/model-rail/track-geometries-for-00-gauge-hornby-setrack/
My impression from some research:
British modelers do mix Hornby100 and PECO100
Peco100 can be mixed with Atlas100
Conclusion Hornby and Atlas can be mixed.
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As with any mixing of track brands, some minor easily acomplished adjustments may or may not be necessary.
I tried to sell my two cents worth, but no one would give me a plug nickel for it.
I don't have a leg to stand on.
Is Hornby track compatible with Atlas track code 100?