See this bug report from player Part-human on my Portal Research mod: https://mods.factorio.com/mods/docpaisl ... sion/16566
Creating a beam that is over ~650 units long seems to then trigger a corruption error upon saving the game. Not sure what the best behaviour would be but either a) support very long beams in the save file, or b) enforce a limit on beam length, perhaps refuse to create the beam and/or display an error. Very long beams are probably bad for performance anyway!
