You can't!! There is no railway to Dalhousie and never has been. There IS a station called Dalhousie Road just 10kms out of Pathankot on the narrow gauge Kangra Valley line from Pathankot to Joginder...
For normal/good conditions, a basic road bike is fine. For uphill, you're generally looking at the weight of the bike, and aerodynamics won't come into play too much for riding under around 15mph or...