Around India in 80 trains The journey began in my old home of Chennai. I boarded the 14-hour Anantapuri Express to Nagercoil, a short hop from Kanyakumari - the southernmost point of India, where the Arabian Sea, the Indian Ocean and the Bay of Bengal all meet. After witnessing a total solar eclipse from its rocky shores, I threaded up the glorious Konkan coast, hanging out of the doors of the Mandovi Express as it sailed across the Panval Nadi Viaduct - the highest in India - the sea shifting quietly below, before sipping Bombay Sapphire on the Indian Maharaja Deccan Odyssey and spotting tigers fight in Ranthambore, tackling Mumbai's local trains at rush hour, visiting the world's first hospital train in Madhya Pradesh, and wedging myself into luggage racks on trains to Dwarka, Udhampur and Ledo, the western, northern and easternmost tips of the network. Within the first few days, I realised that an Indian train ticket is a permit to trespass on the intimacies of other people's lives. What would have been improprieties elsewhere become instantly acceptable on a train: tearing strips of roti proffered by a man I had known for 10 minutes; reading in bed while eyeing a dishevelled stranger muttering in his sleep; eavesdropping on young lovers" disputes; or gatecrashing the celebrations of pilgrims and wedding parties, clapping and singing along as their gifts of glass bangles slid down my arms. Suddenly my destination would rap at the window, rudely interrupting and bringing a curtain call on the show. I soon learnt some tricks of the trade. On several journeys the train halted in between stations and, after 20 minutes or so, jerked and carried on while passengers remained nonplussed, playing cards or chatting in the vestibules. Wondering what was causing the unscheduled stops, I questioned a fellow passenger, who explained that the label on the emergency handle saying PULL HANDLE TO STOP was often taken quite literally. Passengers passing through their villages would yank the handle, jump off and skip across the tracks to their homes. "There are so many people on the train," he said, "by the time the conductor has reached the carriage, who knows who pulled what?" Inevitably, after almost four months constantly on the move, a part of me did begin to go a little crazy. I had spent more nights contorted in a rocking berth than I had stretched out on a stationary bed. My back was filled with knots and the May heat was making me irrational and snappy. Contrary to the romanticised descriptions of India's smell of sweet chai and spices, the honking of horns, the stench of sandalwood and sewers, and the close proximity of sweating skin began to batter my senses, but one remedy that always worked to counter the situation was to squat on the steps of the doorways, watching the sun go down. Most trains travel so slowly that passengers regularly loop arms through the hand holds, invigorated by the blast of warm air, or perch on the steps with a battered paperback. Watching sunsets as the train rolled through the countryside became a daily ritual, the sun turning orange, darkening to a deep pink, then slowly sliding away, leaving cracks of soft light lingering in the sky. For many, Indian Railways provides little more than a mode of transport: a cheap and convenient way to commute, visit relatives or simply while away the day. For others, it is a place of employment where generations have earned their livelihood. But after 80 journeys, 25,000 miles and a thousand cups of tea, I realised that it really is the bloodstream that keeps India's heart beating. Around India in 80 Trains by Monisha Rajesh is published by Nicholas Brealey (£10.99). It can be ordered through Telegraph Books (0844 871 1515; books.telegraph.co.uk) for £10.99 plus £1.35 p&p. Planning your own Indian odyssey Where to start Booking train tickets from outside India has recently become more awkward, with the need for an Indian mobile phone number to be entered when making reservations, although there are ways around this. The Man in Seat Sixty-One (seat61.com) offers an excellent, up-to-date guide to the ticketing bureaucracy, costs and classes. But the best bet is to visit Shankar Dandapani, the British representative for Indian Railways (indiarail.co.uk), at his Wembley office, where he can help you to plan routes, book journeys and provide you with a prepaid Indrail pass if you plan on taking a number of trains. Other useful sites include indiarailinfo.com and cleartrip.com, which charges a small fee to book tickets, but accepts all foreign credit cards. Possible routes Indian Railways has something for every kind of person, time-frame and budget. If you're pushed for time, start in Mumbai and travel down to Mangalore via the Konkan railway - a 475-mile stretch with the Arabian Sea on one side and the Sahyadri Hills on the other. Then take the Yeshvantpur Express through the lush green Western Ghats to Bangalore, one of the most scenic routes on the entire network - particularly through Sakleshpur and Hassan - filled with waterfalls, coconut groves and bridges. If you want to travel in grand style, try the seven-night Pride of the South tour on the Golden Chariot (thegoldenchariot.co.in), which starts in Bangalore and weaves through Mysore, Kabini National Park, Badami and the World Heritage Site at Hampi to Vasco da Gama in Goa. How does it all work? The booking system opens locally 120 days in advance of a journey, so plan for long journeys and overnight trips. However, it is fine to turn up at the station for short hops and local passenger trains. Most major cities have a foreign tourist desk, where you can take advantage of the foreign tourist quota on certain journeys, and female travellers can go to the ladies-only counters for faster service. There are eight classes, from first class air-conditioned to general unreserved, so work out which suits your needs and budget. There is also a "tatkal" - meaning "immediate" - system for last-minute travel, under which a handful of tickets is released at 10am the day before a train is due to depart. What's the food like? Meals are included in the fare on Rajdhani, Shatabdi and Duronto trains, while Indian Railways catering staff come around to take orders on other trains soon after departure, returning to collect payment and tips after you're finished. If you're jumping out at stations to eat the platform snacks, eat freshly cooked hot food and drink bottled water such as Aquafina or Kinley. Keep a stock of apples, biscuits and banana chips in case it's a while before the next stop. Dos and don'ts Be courteous to your companions and follow the rules for putting down berths and switching off lights at 9pm. Take phone calls in the vestibule and keep noise to a minimum. Others may not observe this, but it doesn't mean you shouldn't. Don't throw your rubbish in the bin under the sink - it just gets flung out of the door later. Keep it tied up and take it when you get off. Women travelling alone on overnight services should book into AC3tier and above and choose an upper berth to be out of reach of wandering hands. Claustrophobics won't enjoy the upper berth of the AC3tier compartment as the distance between your nose and the ceiling isn't huge. The same goes for the side upper berth, which is ever so slightly narrower than the others. Its three closed sides and drawn curtain give the feeling of sleeping in a moving coffin.