After Jammu–Baramulla line, Bilaspur–Leh line will be the most challenging railway project in Indian Railways due to high mountains, a large number of tunnels and high bridges and severe cold weather.date=December 2012 According to the survey report, cost of construction of this 498 kilometers long all weather broad gauge railway line has been calculated at Rs 83,360 crore with a negative rate of return of 4.46%.