If you really want this tone, BGelais has pretty much nailed it - and also Kill Em, And Justice, etc. using amp sims, impulse responses, chorus and limiter.
As far as getting that tone on the POD500, I've tried using similar settings and wasn't happy with the results. I'm sure someone better at tweaking could do it though.
James used a Marshall and a tube screamer for this one, and said they had a hard time in the studio trying to get a good sound - hence the chorus ,limiter and, gate.
His modded Marshall head from KillEm was stolen before RTL was recorded.
This is in my opinion the heaviest and best metal guitar sound ever recorded, I fell in love with RTL as a kid and still think it holds up to this day.
Funny James hated it and never used it again, using Mesa Boogies after this...