The Kalka-Shimla Railway built to connect, the summer capital of India in 1903 at an altitude of 2076 meters offers a panoramic feast to experience the grandeur of the picturesque Himalayas from the shivalik foot hills at Kalka to several important points such as Dharampur, Solan, Kandaghat, Taradevi, Barog, Salogra, Summerhill, Shimla and beyond up to the silvery snow line near the towering peaks. On June 29, 1898, a contract was signed between the secretary of state and the Delhi-Ambala-Kalka railway company for construction and working of a two feet gauge line from Kalka to Shimla. As per the contract, the rail line was to be built without any pecuniary aid or guarantee from the government. The land was, however, provided free of charge.

The military authorities were skeptic about the narrower gauge of two feet chosen for Kalka-Shimla Railway. They recommended a standard two feet by six inches gauge for mountain and light strategic railways. The government of India yielded to the military requirements and on November 15, 1901, the contract with DUK was revised and two feet by six inches gauge was adopted for Kalka-Shimla Railway. This meant change of gauge for a portion of the line built in the year 1901.

In the beginning, the line was laid with 41-1/4 lb flat footed steel rails 21 feet long on steel bearing Paltes and Deodar timber sleepers, nine to a rail. The tack was stone ballasted throughout and fenced only along the Kalka camping ground and through the outskirts of the town of Kalka.

The line measuring 59.44 miles from Kalka to Shimla was opened for traffic on November 9, 1903. Because of peculiar working conditions-high capital cost coupled with high maintenance cost-Kalka Shimla railway was allowed to charge higher rates and fare compared to the then prevailing rates for other lines in the plains. By 1904, a total of Rs. 1,65,25,000 was spent by DUK and it was a serious financial crisis. On representation of the company, the secretary of state decided to purchase the line, the purchase was affected from January 1, 1906.

An interesting feature of the Kalka-Shimla Railway is the almost complete absence of Girder bridges. Multi arched galleries like ancient roman aqueducts being the commonest means of carrying the line over the ravines between the hill spurs. There is only on 60 feet plate girder span in a Pinewood near the old engineer bungalow at Dharampur and a steel trestle via duct, which replaced a stone gallery in 1935 in the 869 bridges representing about 3 percent of the line. The entire section has been built with steep gradient through the Shivalik ranges.

Another special feature of the Kalka-Shimla Railway is that as many as 27 cutovers serve as different gradient crossings. There are 20 intermediate stations, and all have crossing facilities. The line also has about 107 tunnels, which, besides representing the engineering feat, also generate a lot of interest in the travellers. During summer months, passenger traffic is heavy whereas in winter months, potato traffic keeps the line busy.