This kind of writing seems to be the equivalent of Normschrift in the US; it's all over schematics from the 60s and 70s (sometimes even the 80s). Just like Normschrift written by craftsmen it looks super-regular, almost like computer set type, except it has tiny variations between draftsmen, making it clear it is actually written by hand. (Some people use templates to write Normschrift; a looked down upon practice, generally not permissible in exams).