When using the train crossing parts, make sure to build them first and use them as a start to go build your perimeter. Otherwise it could be that the modules do not align properly.
I build this for late game where the evolution factor is 1 (100%) that is why the requester chests request uranium ammo. This wall should be able to hold itself against vanilla biters easily. Damage is reapaired by repair turrets (https://mods.factorio.com/mod/Repair_Turret).