I am also in favour of the extension of the M3 Parkway line to Navan. I believe reopening the line as it was is perfectly acceptable, if a more direct and quicker route cannot be found. If a route that is just as direct cannot be found, the rebuilding of the line through Dunsany should be done. The line was previously in state ownership and should remain so; state land should not be freely given away to private land owners to do what they will, no matter how altruistic the cause. It would also add unnecessary time to the train journey.
The only time-adding diversion to the route that would have merit would be closer alignment of the railway station at Dunshaughlin towards the village.