Thanks guys.
Yes, I'm not taliking about high/ low enroute charts.
I had a look at those pages (57) and compared them to enroute charts. Some airways are designated for example UG854 which would mean according to 126.9's explanation and also what I found in the Jepp that it's an RNAV route....but, why then do you get routes that will be UM974R , with the "R" clearly indicating that it is an RNAV route. Wouldn't this be like saying the same thing twice?
Cheers,
TL