THE 96.54-km-long Kalka-Shimla narrow gauge track has 102 operational tunnels that constitute about 8 per cent of the total length of the route. This rail track, which was open to passengers on November 9, 1903, is a living tribute to those engineers who dared to bore a total of 107 tunnels and set an example of how a railway line could pass through a rough mountainous terrain without destroying the splendour and beauty of the hills.

The tunnels were renumbered in 1930, as some of them were found to be defunct. From 107, their number was reduced to 103, and this was further came down to 102 when tunnel no. 46 near the Solan Brewery had to be demolished.

The two of the longest tunnels on this track are at Barog and Tara Devi. All the tunnels were built between 1900 and 1903. L. Edwards, Executive Engineer of Dharampur division, completed work on as many as 30 tunnels. Railway chronicles say workers used large mirrors and acetylene gas to illuminate the tunnels. The longest tunnel on this track is the Barog tunnel (no 33). It is named after Barog, a British railway engineer.

This 1143.61-metre-long tunnel, which passes through fissured sandstone, has a tragic story associated with its construction. Barog, who was in charge of this tunnel, committed the mistake of digging the tunnel from both ends of the hill. Both ends of the tunnel could not meet due to wrong alignment. It is said that the British authorities fined Barog Re 1 for wasting government money in the tunnel. The British engineer could not digest this humiliation and during a walk along with his pet dog, shot himself in sheer desperation. He killed himself near what now is the state government-run Barog Pine Wood Hotel. It is said that his dog upon seeing his master bleeding profusely ran in panic to a village, near the present Barog railway station, for help. However, by the time people reached the spot, Barog had breathed his last.

There are different versions about the suicide as some say the dejected engineer shot his dog before he shot himself. He was buried in front of the tunnel, near the Kalka-Shimla national highway, about 1 km from Barog. Ironically neither the Railway authorities nor the state government has done anything to maintain his grave. A signboard giving details about the sad end of Barog was put up near his grave but that too has now disappeared. As a result, it is now even difficult to locate the whereabouts of his grave. The forlorn tunnel has now been closed. The tunnel has a natural water source that meets the water demand of the Special Service Bureau (SSB), Dharampur.

After the death of Barog, Chief Engineer H.S. Harrington was given the charge to dig a new tunnel. The new tunnel was constructed about 1 km away from the earlier point with the guidance of Bhalku, a local saint from Jhaja, near Chail.

Bhalku possessed natural engineering skills and it is believed that he also helped the British engineers to bore other tunnels on the track. According to Simla Gazette, the Viceroy presented Bhalku a medal and turban which are still treasured by his family. As much as Rs 8.40 lakh was incurred on the Barog tunnel. Work on it started in July 1900 and completed in September 1903. Many workers, most of them Indians, died during its construction. Trains, running at 25 kilometre per hour, take 2.5 minutes to cross the tunnel.

The 992-metre-long Tara Devi (no. 91) tunnel was built at a cost of Rs 3.04 lakh. Since a shrine stood on top of the Tara Devi mountain, locals were of the view that the goddess of the shrine would never permit the construction of the tunnel. One day, work had to be even stopped, as there was panic among the workers following rumours of a huge snake in the tunnel. The work was resumed only when it was found a large iron pipe running along the tunnel for providing fresh air had been mistaken for the serpent.