Could you clarify this part
...when i ping the ethernet port either from the local or the remote router I get success rate
ranging from zero to 100 percent.
where are you pinging from?
enet1-14k-line-enet2
are you able to ping enet2 from rtra but cannot ping the rtrb serial interface?
Does rtra have a route to enet2; rtrb have a route to enet1?
If you are pinging from a host where is it located, is one of these routers its gateway router?