Bhutan Tips:
It is the nearest rail head for visiting bhutan.
From hasimara ,the nearest entry point of bhutan is Phuentsholing which is 17 km away. Regular Buses goes via hasimara to Phuentsholing. Basically These buses start from Silliguri and go via hasimara to Phuentsholing only. Or else regular share taxi/cabs are also available from hasimara.
No permit is required...
more...

for entering Phuentsholing. But do keep a caution, Last bus/taxi probably from Phuentsholing to thimpu/paro leave at mid afternoon as check posts in route get closed during night time. The entry gate from India closes at 20:30 (IST). Bhutan time is half hour ahead of Indian time. You can stay in hotels in Phuentsholing without permit. Permit is made at Phuentsholing for onward visit to Thimphu and Paro only. For visiting other places in Bhutan like Panakha , permit is made at Thimphu.
Indians do not require visa to travel to Bhutan, but need permit. Obtaining the permit may take as long as half a day. Permits are issued at Phuentsholing. Identification proof like Voter ID Card or Passport is needed. However, you can also get them at Kolkata. Indians can withdraw Bhutanese currency using their Indian debit card at a charge of IDR20 per transaction. Indian currency is widely accepted, excluding 500 and 1000 rupee notes. However most shops and establishments accept Indian 500 rupee notes. Travel time from Phuentsholing to Thimpu is around 7 hours by road. The road is mostly mountainous, and must be avoided by those with fear of heights.
There are private buses and shared taxis from Phuentsholing to Thimphu but a comfortable option is to book a Bhutan Post bus (Rs/Nu 170) which leaves each morning at 7 AM (Bhutan time) from the post office.