Good discussion. I have different layouts in my home with several different track types.
You can buy as mentioned above the Gargraves in pre curved sections. But you must consider how many joints there are per track section. Depending on the radius you may have 3 or 4 sections of Atlas track compared to the longer Gargraves curved track sections.
A few custom curves are easy to bend not much work if careful.
It is really important to have as few track joints for good electrical and signal contact.
The longer your tracks sections the better.
For straights Gargraves is easier to cut then Atlas to length just buy a case of the straights.
I have had problems with the Atlas turnouts the switch machines do not stay connected well and need to be fixed or reconnected occasionally.
The Gargraves new improved turnouts actually work very well but Ross are best.
Again Gargraves and Ross have excellent stock and selection good pricing and are made in US.
Atlas over seas.
