UNESCO Heritage Railways of India: Darjeeling, Nilgiri & Kalka–Shimla

Tucked into the mountains of India — the eastern Himalayas, the Nilgiri Hills, and the Shivalik ranges — are three narrow-gauge railways that represent some of the most extraordinary engineering achievements of the 19th and early 20th centuries. Collectively inscribed as the "Mountain Railways of India" on the UNESCO World Heritage List, the Darjeeling Himalayan Railway, the Nilgiri Mountain Railway, and the Kalka–Shimla Railway stand as monuments to human ingenuity in the face of terrain that defeated many an early railway engineer. The first inscription was awarded to the Darjeeling Himalayan Railway in 1999. The Nilgiri Mountain Railway was added as an extension in 2005, and the Kalka–Shimla Railway followed in 2008. What sets these railways apart from most other World Heritage Sites is that they are not static monuments — they are living, working railways that carry passengers, employ thousands of people, and traverse landscapes of profound ecological and cultural significance every day that they operate.

The significance of these railways is not purely historical. Each one represents an elegant engineering solution to the specific challenges of its terrain. The Darjeeling line uses loops and reversals to wind up Himalayan foothills without tunnels or racks. The Nilgiri line employs a Swiss-designed rack-and-pinion system to conquer the steepest scheduled gradients in India. The Kalka–Shimla line bores through 103 tunnels and spans 864 bridges across the Shivalik Hills in just 96.6 km. And all three continue to serve real communities — commuters, traders, students, and pilgrims — alongside the heritage tourists who come to ride them for pleasure. UNESCO's recognition of these railways honours both the exceptional engineering represented and the living heritage they embody: the communities whose daily lives have been shaped by the railway for over a century.

Darjeeling Himalayan Railway (DHR) — The Toy Train of the Himalayas

The Darjeeling Himalayan Railway covers 88 kilometres of 2-foot (610 mm) narrow-gauge track from New Jalpaiguri on the West Bengal plains to the famous hill town of Darjeeling at 2,134 metres above sea level. The line was built by Franklin Prestage, an agent of the Eastern Bengal Railway, and construction was completed between 1879 and 1881. The engineering challenge was formidable: to climb over 2,000 metres of altitude through the subtropical foothills of the eastern Himalayas, across steep spurs and across ridges, without the benefit of modern earth-moving machinery, tunnels, or rack-and-pinion assistance. The solution was a series of ingenious loops and reversals — places where the line literally doubles back on itself to gain altitude — that allowed the gradient to be kept within the adhesion capability of the small B-class steam locomotives. This approach made the DHR the prototype for mountain adhesion railways across the world and contributed directly to its UNESCO listing in 1999 as the first Indian railway to be inscribed.

The most celebrated of the DHR's engineering features is the Batasia Loop near Ghum, where the track curves through a complete 360-degree spiral around a central mound, crossing over itself on a small bridge before continuing upward toward Darjeeling. At the centre of the loop, a war memorial honours the Gorkha soldiers who gave their lives in India's wars, and on clear mornings, the panoramic view of Kangchenjunga — the world's third highest peak at 8,586 metres — from the loop is one of the most spectacular mountain vistas accessible from any railway in the world. Ghum station, at 2,258 metres above sea level, holds the distinction of being the highest railway station in India. Its small locomotive museum displays restored B-class steam engines and historical artefacts from the DHR's 140-year history. There is also a persistent legend of ghost sightings at some of the quieter intermediate stations — a layer of folklore that has grown around the railway over generations and adds to its atmospheric appeal for visitors.

The B-class locomotives that have earned the DHR the affectionate nickname "Toy Train" are 0-4-0T saddle-tank steam engines, some dating to the 1880s and 1890s, manufactured by Baldwin Locomotive Works in the United States and Sharp Stewart & Co. in the United Kingdom. Several remain in working order and are used for heritage steam specials, most famously on the popular Darjeeling–Ghum Joy Ride, a 13 km return trip that is operated daily for tourists. Watching one of these century-old engines in active steam, navigating tight curves through the tea gardens above Darjeeling with its characteristic whistle and a trail of coal smoke, is a railway experience that has no equivalent elsewhere in India. The full New Jalpaiguri to Darjeeling service takes approximately seven to eight hours — a pace that is entirely the point, allowing passengers to absorb the extraordinary panorama of the eastern Himalayan foothills at leisure.

Nilgiri Mountain Railway (NMR) — The Rack Railway of the South

The Nilgiri Mountain Railway connects Mettupalayam on the Tamil Nadu plains to Ooty (Udagamandalam) in the Nilgiri Hills, covering 46 kilometres on metre-gauge (1,000 mm) track and rising from approximately 326 metres to 2,203 metres above sea level. The line was constructed between 1891 and 1908 by the Madras Railway under British India and uses one of the most remarkable engineering solutions in Indian railway history on its lower section: the Abt rack-and-pinion system, developed by Swiss engineer Roman Abt in the 1880s. A central toothed rack rail runs between the two running rails on the section between Mettupalayam and Coonoor. The locomotive carries a matching pinion gear that meshes with this rack, providing mechanical grip on gradients as steep as 1 in 12 — the steepest on any scheduled passenger railway in India. This rack section was designated a UNESCO World Heritage Site as an extension of the Mountain Railways of India inscription in 2005, recognising the extraordinary engineering of the rack system and the NMR's significance as the only rack railway in India.

Coonoor is the operational base of the NMR and the point at which the rack section ends. From Mettupalayam to Coonoor, the heritage train is hauled by the magnificent X-class steam locomotives — purpose-built rack-and-pinion engines made by the Swiss Locomotive and Machine Works (SLM) — that push rather than pull their coaches up the mountain (a safety measure ensuring that if a coupling fails, the coaches cannot run away downhill). The sound of an X-class engine working hard on the rack section — the mechanical clicking of the pinion meshing with the rack teeth overlaid with the rhythmic exhaust of the steam — is unlike anything else in Indian railway travel. Above Coonoor, the upper section to Ooty uses diesel traction on conventional adhesion track through the Nilgiri plateau. Stations passed on the full journey include Kallar, Hillgrove, Runnymede, Coonoor, Wellington, Lovedale, and Ooty — each with its own character and scenery, from the tropical forest of the Kallar valley to the eucalyptus and tea estate landscape of the upper plateau.

The Nilgiri Mountain Railway passes through the Nilgiri Biosphere Reserve, one of the most ecologically sensitive protected areas in India — home to Asian elephants, leopards, Nilgiri tahrs, and hundreds of endemic plant species. The railway's narrow gauge and low operational speed minimise habitat disturbance compared to a road of equivalent capacity, making it an environmentally appropriate mode of transport through a UNESCO-designated biosphere. This ecological dimension adds a further layer of significance to the railway's heritage value: the NMR is not only a monument to engineering ingenuity but a demonstration that 19th-century infrastructure can be compatible with 21st-century conservation priorities. The line carries both daily commuter services for residents of the Nilgiris district — students, workers, traders — and heritage tourist trains for the visitors to Ooty, making it one of the few UNESCO World Heritage Sites that also functions as essential public transport for a living community.

Kalka–Shimla Railway (KSR) — The Railway to British India's Summer Capital

The Kalka–Shimla Railway covers 96.6 kilometres on 762 mm narrow gauge from Kalka in Haryana to Shimla in Himachal Pradesh, climbing from 656 metres to 2,076 metres through the Shivalik Hills in a continuous sequence of tunnels, bridges, and curves. The line was opened on November 9, 1903, built by the Delhi–Ambala–Kalka Steam Tramway company for the explicit purpose of providing the British colonial administration with a comfortable and reliable rail link to Shimla — British India's summer capital. From May to October each year, the Viceroy, the entire colonial government apparatus, hundreds of civil servants, their families, and the social world of imperial India would migrate to Shimla to escape the heat of the plains, and the KSR was their lifeline. A special Railway Motor Car — a small self-propelled luxury railcar — was maintained for the exclusive use of the Viceroy and senior officials, a predecessor of the modern presidential saloon. The railway's association with Shimla's imperial history gives it a political and cultural significance that extends well beyond its engineering achievements, and this combination of outstanding engineering and historical importance was recognised when the KSR was added to the Mountain Railways of India UNESCO World Heritage Site in 2008.

The engineering statistics of the KSR are staggering. In 96.6 kilometres, the line passes through 103 tunnels, crosses 864 bridges, and navigates 919 curves. The longest tunnel is the Barog Tunnel, measuring 1,143 metres, which carries one of Indian railway construction's most poignant legends. A British engineer named Colonel Barog was assigned to bore the tunnel from both ends simultaneously, but his calculations were incorrect and the two bores failed to align — a costly mistake that resulted in financial penalties and public disgrace. According to the most widely repeated version of the story, Barog was so overcome by the humiliation that he took his own life before the tunnel was completed. The tunnel was subsequently resurveyed and correctly completed by H.S. Harrington. Barog station — located near the tunnel portal — bears the engineer's name to this day. The tunnel is one of the most atmospheric spots on the KSR journey, and the legend of Colonel Barog has become part of the railway's living folklore. The 864 bridges on the line include several multi-arch stone viaducts that are engineering achievements in their own right, carrying the railway across deep Shivalik gorges with a structural grace that has survived over 120 years of mountain weather.

The KSR currently operates several train services including the Shivalik Deluxe Express, the Himalayan Queen, and a heritage Rail Motor Car service. The Shivalik Deluxe Express is the most popular tourist service, with panoramic windows and improved seating, covering the full Kalka–Shimla route in approximately five to six hours. Scenery changes dramatically as the train climbs: the early departure from Kalka passes through flat agricultural land before the first Shivalik foothills appear. By Dharampur, the train is winding through cedar and oak forests. The intermediate stations — Solan, Kandaghat, Shoghi — offer glimpses of valley depths and ridge-top villages that feel timeless. Shimla station itself sits on a ridge at 2,076 metres, depositing passengers directly into the heart of the town, from where the famous Mall Road and Ridge are just minutes away. A proposal for a Heritage 5-Star on Wheels luxury service on the KSR has been discussed over recent years, reflecting the railway's enormous potential as a premium heritage tourism product.

Other Heritage Railways of India — Beyond UNESCO

While the three UNESCO-listed mountain railways are the most internationally celebrated, India has several other heritage railways of great historical and scenic significance. The Matheran Hill Railway in Maharashtra is a 20 km narrow-gauge line (2-foot gauge) from Neral Junction to the hill resort of Matheran, built between 1901 and 1907 by Sir Adamjee Peerbhoy. Matheran is the only car-free hill station in Asia, and the railway is therefore its sole mechanised transport link — a functional importance that gives the line ecological and social significance beyond heritage tourism. The Matheran Hill Railway is operated by Central Railway, passes through lush Western Ghats forest, and has been on India's tentative list for UNESCO inscription, though not yet formally nominated. The railway faces recurring challenges from monsoon landslides but continues to operate as a lifeline for the Matheran community and a popular weekend destination for visitors from Mumbai and Pune.

The Kangra Valley Railway in Himachal Pradesh connects Pathankot in Punjab to Jogindernagar in the Kangra Valley over 164 km on 2-foot 6-inch narrow gauge, built between 1926 and 1929. The line passes through the scenic Kangra Valley with the Dhauladhar range of the Himalayas as a backdrop, crossing 993 bridges and 2 tunnels. The views of snow-capped Dhauladhar peaks from the train — particularly during winter and early spring — are extraordinary, and the line serves local communities throughout the valley as well as attracting heritage railway enthusiasts. The Kangra Valley Railway has been advocated for conservation investment and has been discussed as a potential future UNESCO nomination by heritage railway preservation groups who believe its scenic and historical significance merits international recognition.

Conclusion: Preservation, Tourism, and Sustainable Heritage

The preservation of India's mountain heritage railways requires a sustained commitment of resources, expertise, and institutional will that is not always easy to maintain for a public railway system facing enormous pressures across its vast mainstream network. The UNESCO inscription has been an important catalyst for this commitment, bringing international attention and in some cases external funding and expertise to support restoration projects. Heritage steam operations on the Darjeeling and Nilgiri lines are expensive — a working steam locomotive requires far more maintenance, skilled labour, and specialist parts than a diesel or electric equivalent — but they are justified by the unique tourism premium and the cultural value of keeping these engineering traditions alive. The Kalka–Shimla Railway's extraordinary infrastructure of tunnels and bridges requires continuous maintenance in a challenging mountain environment, and Indian Railways has invested in both routine upkeep and periodic major restoration works on the most significant structures.

Tourism revenue from these three railways is significant and growing. The Darjeeling Himalayan Railway, the Nilgiri Mountain Railway, and the Kalka–Shimla Railway collectively attract hundreds of thousands of domestic and international visitors annually, generating substantial income for local economies through accommodation, food, transport, and craft industries that cluster around each railway's corridor. The heritage railway experience is one of the most highly rated by international tourists visiting India, and platforms like the Incredible India campaign have increasingly highlighted these railways as flagship tourism products. At the same time, the railways' role as community transport — carrying schoolchildren to Ooty, traders to Shimla market, commuters from Darjeeling's surrounding villages — gives them a social legitimacy that pure heritage tourism railways lack. This dual identity as both living community infrastructure and world-class heritage tourism product is what makes India's mountain railways genuinely irreplaceable, and genuinely worth every effort required to preserve them for the generations ahead.