The NG route fell into disuse a long time ago, along with several short NG spurs from Bihar to Nepal ( sometime in the 60's or 70's). There have been several plans to revive these old routes to facilitate freight movement between both the countries. So, it is possible that they are reviving this old route again in a BG avatar. The old NG alignment is mentioned in this IRFCA page about connectivity from India to Nepal. ( Just checked in Google Earth, this is just an alignment, and only earthwork is visible in most places, and the connection to Bathnaha is not seen in Google Earth).
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