"Section E (the green pages) lists easements which apply to routeings.
Journeys on direct trains or taking the route of shortest distance or a distance longer
by no more than 3 miles are always following a permitted route. Journeys following a
route given by the Routeing Guide are following a permitted route.
"
[...]
"An easement which extends permission is a positive easement. An easement which
narrows permission is a negative easement. Map, double-back and fare route
easements are always positive. Circuitous route easements are always negative.
Other kinds of easements can be positive or negative.
A journey which follows a route permitted by the Routeing Guide may be forbidden
that route by a negative easement.
When you have chosen your journey, look to see if an easement applies to it."
Looks to me like there is a specific distinction between routes "permitted by the Routeing Guide" and direct/shortest/within 3 miles of shortest routes (even though the third are also permitted by the Routeing Guide, strictly speaking). This would lead me, as bb21 does, to believe that negative easements can't apply to the routes within 3 miles - but I agree that it's rather ambiguous.