I carry my train journeys in my bones, the juddering song of the Indian rail.

The rhythmic clatter of wheels on tracks, the kaleidoscope of faces flashing past the window, the distinct aroma of chai and samosas permeating the air – these are the indelible imprints left by Indian train journeys. India, a land of unparalleled diversity, finds its truest reflection in its vast railway network. As India’s first prime minister, Jawaharlal Nehru, famously observed, India is a palimpsest, a manuscript where no layer quite effaces the one that went before. This analogy perfectly encapsulates the experience of travelling by train across the subcontinent. Each journey etches new narratives onto the mind, yet always reveals the enduring layers beneath: the myriad languages, the distinct cultures, the ever-changing landscapes, and the often-challenging climate, all witnessed through the shared experience of the rail.

My own memories are steeped in this unique mode of travel. I recall vividly a particular journey in 1998 – a summer etched in memory for its brutal heat and the seismic geopolitical tremors of the Pokhran-II nuclear tests. In May of that year, India conducted a series of five underground nuclear weapon tests, sending ripples of shock and awe across the globe. Domestically, while a sense of national pride surged, international condemnation and sanctions followed swift. This charged atmosphere, coupled with an unforgiving Indian summer, created an almost surreal backdrop for my odyssey.

Setting out from Mumbai, then still officially Bombay, I embarked on a thousand-mile (1,600km) journey north to Dehradun in an ordinary three-tier sleeper compartment. The train, already frazzled by the oppressive conditions, soon shed any semblance of a schedule. What should have been a manageable trip stretched past 50 hours, becoming an endurance test. The heat soared past 50°C (122°F), an extreme temperature that physically manifested in the metallic burn on the window grilles, searing to the touch. The wind, instead of offering relief, blew in through the open windows like a hot, killing furnace. Stopping at uncovered platforms in the heart of the country, droplets of water, splashed on faces for a momentary reprieve, would sizzle and evaporate instantly. My rubber soles began to melt, testament to the infernal conditions. Yet, a fortnight later, having completed my expedition from the Arabian Sea to a Himalayan glacier – trekking to the mouth of a tributary of the Ganges – it was possible to look back on that arduous rail ordeal with a surprising sense of affection, a harsh but ultimately rewarding initiation into India’s raw, unvarnished reality.

This profound connection to Indian railways, its blend of the intimate and the epic, inevitably seeped into my creative work. I often wonder if that heat-addled odyssey unconsciously influenced the journey of the runaway protagonist in my novel, Railsong. Physically depleted by her own trials, she finds sustenance in the unexpected benevolence and solidarity of strangers encountered on her travels. Alighting in the great city of Bombay, beneath the imposing gargoyles of the gothic masterpiece then known as Victoria Terminus (now the Chhatrapati Shivaji Maharaj Terminus, or CSMT), she recognizes that she has emerged on the other side of a profound transformation, much like I did after my 1998 journey.

The Chhatrapati Shivaji Maharaj Terminus, a UNESCO World Heritage site, is more than just a railway station; it is a monument to Victorian Gothic Revival architecture blended with traditional Indian elements. Its intricate stone carvings, grand domes, and majestic facade speak of a bygone era, yet it remains a pulsating hub of modern India, a gateway to the city’s ceaseless energy. Its renaming from Victoria Terminus reflects a broader post-colonial effort to reclaim Indian identity, scrubbing away the colonial fingerprints from historical landmarks.

In no other activity, so easily accessible to all strata of society, does India reveal itself as wholly as through train travel. Mahatma Gandhi, initially a vocal critic of the railway system, eventually came to embrace its power. In his seminal work, Hind Swaraj (1909), he argued that railways, along with other symbols of modern civilization, "accentuate the evil nature of man" by facilitating the spread of disease, famine, and ultimately, British colonial control. However, upon his return to India from South Africa in 1915, Gandhi famously embarked on a year-long Bharat Darshan (tour of India) by rail, predominantly travelling in third-class compartments. This immersive experience fundamentally altered his perspective. He realized that the railways, despite their colonial origins, were an unparalleled tool for understanding the diverse fabric of his nascent nation, for connecting with the masses, and for fostering a sense of shared identity. He understood that to know India, one must travel its rails.

This is why I often recommend to prospective travellers not necessarily the famed heritage or scenic routes – though these are undeniably captivating and worth experiencing. By all means, sample the quaint narrow- or metre-gauge hill railways like the Darjeeling Himalayan Railway (the "Toy Train") or the Kalka-Shimla Railway, both UNESCO World Heritage sites offering breathtaking mountain vistas and engineering marvels. Or embark on the gorgeous run down the Konkan coast, a spectacular stretch of railway threading through tunnels and over viaducts, showcasing India’s biodiverse Western Ghats and pristine coastline. But beyond these curated experiences, I advocate for using the railways simply as a utilitarian way of getting from one place to another. It is in these ordinary journeys that the true essence of India unfolds.

In the process, one learns much about oneself, too. Consider the intimate setting of sleeper travel. Is there a situation more exposing, more conducive to self-reflection and connection, than sharing a confined compartment with strangers for hours, sometimes days? With a stroke of luck, you might stumble upon invigorating company. A few months ago, I made an overnight trip from Mumbai to Delhi. My companions were three large policemen, each initially taciturn: one nursing an injured toe, another engrossed in his newspaper, the third absorbed by his phone. As the journey unspooled, so too did their stories. They were en route to capture a suspect. They recounted a previous expedition to Delhi where a slippery accused murderer led them on a chase spanning over 600 miles across three states, a testament to the logistical complexities and sheer determination involved in cross-jurisdictional police work in India. Such exploits, they mused, often make headlines. Another anecdote involved a painstaking manhunt that took them to Mangaluru on the south-western coast. There, instead of their intended target, they discovered the fellow’s namesake – who himself was wanted in a decades-old riots case. That unexpected turn of events led to a medal, a small but significant recognition for their relentless pursuit of justice. These encounters transform mere travel into a profound exchange of human experience, revealing the lives and struggles of ordinary Indians.

Food is another invaluable companion on the rails, an integral part of the Indian railway experience, a culinary journey in itself. While dedicated dining cars are largely a thing of the past, and regulations about open flames have unfortunately restricted the vibrant platform fare of yesteryear, and the foil-boxed meals served on premium services often trigger thousands of official complaints and much casual grousing – eating remains a crucial, almost ritualistic railway habit. The beauty lies in the regional specialties that emerge at various halts. Depending on the season and your chosen route, it is still possible to pop out onto the platform during a brief halt and buy top-notch, farm-fresh produce: succulent lychees from Bihar, creamy custard apples from Maharashtra, sweet bananas from the south, or the king of fruits, mangoes, in places famed for them.

On the bustling Mumbai-Pune route in the west, vendors at Karjat station align themselves strategically with carriage doors, bearing metal trays laden with the town’s famed vada pav. This iconic Maharashtrian street food consists of a deep-fried, lightly spiced potato ball (vada) nestled inside a soft bread bun (pav), accompanied by a mix of dry and wet chutneys – the dry garlic chutney being a safer choice for the cautious traveller, while the spicy green chili and tangy tamarind chutneys add layers of flavour. Further along the same route, as the powerful "banker" engines push the coupled carriages (rake) up the steep gradients of the Western Ghats, the picturesque hill station of Lonavala offers its famous chikki – an energy-boosting sweet made from nuts (peanuts, cashews, sesame) and jaggery (unrefined cane sugar). For those with a more decadent palate, Lonavala also tempts with its rich chocolate walnut fudge.

Venturing into the southern states of Telangana and Karnataka, one might, as I did a few years ago, treat themselves to vividly peppy breakfasts of ograni. This delightful concoction is a mixture of soft puffed rice and an array of condiments and spices, unique to the region. It is similar yet distinctly different from the crunchy, mustardy puffed-rice jhalmuri of Bengal in the east, which owes its pungent kick to mustard oil and an assortment of finely chopped vegetables and spices. And, of course, there is always the enduring prospect of packing a generous tuck of homemade food and sharing it with any friends, old or new, made along the way. This act of sharing food on a journey is a quintessential Indian experience, forging bonds over simple meals.

Despite the myriad challenges that Indian train travel can present – delays, overcrowding, occasional discomfort – the journeys themselves are almost always pleasurable and remarkably affordable, not to mention significantly more sustainable than air travel. For these compelling reasons, my family and I prioritize rail for as much of our travelling as possible. Routinely, we curve out east from Delhi, traversing the vast swathe of the Gangetic plains, watching the dusty brownscapes gradually transform into vibrant green. We continue up past the trim tea gardens nestled in the eastern Himalayan foothills, through the narrow, strategically vital corridor famously known as the "chicken’s neck" (officially the Siliguri Corridor, a slender land strip connecting India’s northeastern states to the rest of the country), and finally into bamboo-shaded Assam, to my wife’s ancestral home. This journey, typically scheduled for 24 or 28 hours depending on the service, sometimes stretches past 35. Our two young girls, surprisingly, don’t mind; they find flights claustrophobic, preferring the open spaces, the constant movement, and the unfolding drama of the train.

The causes of these delays are often as dramatic as they are instructive about Indian life. One unforgettable instance involved a station footbridge collapsing under the immense weight of Kumbh Mela pilgrims in the town then known as Allahabad (since renamed Prayagraj by a regime intent on scrubbing Islamic fingerprints off Indian history). The disaster, which tragically claimed over 40 lives, was exacerbated by a last-minute change of platforms, triggering a stampede. This devastating event put into perspective my trivial discomfort of waiting in the chilly hours for the train to pull into Mughalsarai (also renamed, after the right-wing ideologue Deen Dayal Upadhyaya). These name changes themselves speak volumes about the ongoing cultural and political shifts in contemporary India.

On another occasion, a derailment, a not uncommon occurrence on the sprawling network due to factors like aging infrastructure or human error, sent us on a circuitous gallivant through the states of Bihar and Bengal, transforming a direct route into an unexpected scenic detour. Then there was the time our rake first mowed down three cows – a sadly frequent hazard on Indian tracks, where livestock often wander freely – and then, in the middle of the night, smashed into a stalled Jeep. Fortunately, the occupants of the Jeep managed to escape. Unfortunately, this is not always the case.

I distinctly recall a monsoonal Assamese morning in 2012. The train I was on, an inexpensive regional service fitted with unreserved bench-seating – in Indian Railways parlance, a "passenger" train – came to a standstill beside a paddy field. These trains are known for their frequent, often seemingly arbitrary, halts, but even by those standards, this seemed like an eccentric location. Eventually, compelled by curiosity, I climbed off to investigate. In front of the locomotive lay a mangled autorickshaw. Alongside the tracks, the bodies of three men had been reverently laid out. Such incidents, tragic as they are, underscore the raw realities of life and transportation in India.

I don’t recount these experiences to deter you from passenger services. In fact, quite the opposite: I highly recommend them. In a land as diverse as India, a passenger train offers a full-blooded immersion in the local tapestry: the distinctive regional dress, the fresh produce carried by farmers to market, the unique street food vendors serve up at each stop, and the unknown halts that mail and express trains roar past, which are, in themselves, the vibrant centres of their own little worlds. After all, on the railways, as in certain great novels, the intimate and the epic, the local and the national, are inextricably linked, weaving together to form the rich, complex whole that is India.

Rahul Bhattacharya’s latest novel, Railsong, is published by Bloomsbury (£18.99). To support the Guardian, order your copy at guardianbookshop.com. Delivery charges may apply.