Bhutan and Nepal are nestled in the lap of the Himalaya, whereas the mountain range forms the northern boundary ofIndia. Rugged topography of the range probably deters from laying the railway tracks in these regions. Train services are either absent (Bhutan) or very limited (India and Nepal).
For instance, toy trains run up to famous hill resorts in Himachal Pradesh (Kangra and Shimla) and West Bengal(Darjeeling) inIndia. If you are entering into Nepal from India, you can board narrow gauge train linking Jaynagar (Bihar, India) to Janakpur and Bijalpura (Nepal). Principal means of intra transport within these three regions is thus still a network of roads throwing several driving challenges. So, plan, pack and prepare for rough road journeys if you want to explore the Himalaya.