We used to use raddle red for engineering marking and indication in exactly the same way as engineering blue. It was made from an iron oxide mixed with oil to produce a paste, I suspect that this is the origin of the term. Although not designed or required to set, dry or cure it would eventually harden and to all intents and purposes look like red oxide paint. This raddle red I beleive pre dated engineering blue and was certainly around in the 1930's if not earlier. It was also a term referring to some sort of colouring used to 'raddle' front door steps! Possibly a Portland cement colouring?