It is 8.30am and choc-a-bloc outside Andheri West, a railway station in Bombay's ramshackle northern suburbs. Ibrahim, the photographer, and I are here to catch a train downtown to the southerly tip of the island city. The thought of the 40-minute ride is making my palms sweat (it's 30C - 86F - and most of me is sweating). The apprehension is understandable. For, as any regular knows, the journey from north to south Bombay is a killer. Literally: 16 people die every weekday on what is, possibly, the world's deadliest stretch of rail. As statistics go, it's an unintelligible gobsmacker - until you experience the rush hour.

Outside the station there forms a tableau of urban Indian life. On the thin strip of pavement, the rag-pickers are sifting through the rubbish. Their kids - “urchins” as the oddly Dickensian local press calls them - sit on their bare bums in the dust. Black-and-yellow auto-rickshaws swarm like diesel-driven wasps. The traffic stops. The driver of a vast red bus has misjudged the turn in the road, pinning himself, and everybody else, in. He is honking his horn (the horns on Indian buses are like clown horns, the ones with the rubber bulbs). He pumps the damn thing, making a noise like a baritone ass with bronchitis, over and over.

The scene helps to explain the railway's popularity. Forget road rage, the traffic situation in Bombay is more likely to induce a deep existential angst. The journey would take three times as long by car. While the traffic remains static, the entrance to the station is sucking up commuters like a black hole swallowing cosmic matter. A deep breath and into the vortex go Ibrahim and I.

Ibrahim, in splendid Indian fashion, jumps a queue of about 40 people to buy a ticket and we head through the heaving chaos for the platform. There is now, in theory, nothing to stop us catching the 9.18 to Churchgate, the main station in south Bombay's commercial district. Within nanoseconds of spying its distant outline, however, I know for sure that there is no way I am going to board this train.

People sprout from every opening of every battered carriage like petunias tumbling out of an armour-plated hanging basket. A few brave (idiotic?) souls cling, somehow, to the sides of the wagons, using the bars that cover the windows as tenuous toeholds. One or two are sitting cross-legged, pictures of serenity, on the roof, inches away from the overhead electric cables. “Nuts,” I say. “Nuts and bananas,” says Ibrahim. The train stops at the platform; I make a half-hearted attempt to get on. The incumbent travellers dangling from the doorway laugh at the imbecile gora (whitey). It is far too busy and I am in a state of amazement.

The problem here is a common one in India, a country where the population has trebled since the 1940s: too many people. Bombay's railway is a third more densely packed than Tokyo's famously congested equivalent. The authorities have coined the term “super-dense crushload” to describe 550 commuters crammed into a carriage built for 200. In the crush, accidents are expected. In Bombay, train stations stock sheets to cover the corpses.

Theories abound that attempt to explain the relationship between India's chronically poor infrastructure and its people. One broadly accepted view is that decades of socialist central planning bred laziness and corruption. Others say that Indians do not work well together. Some argue that a faith in reincarnation colours the average citizen's take on what merits a justified risk. As a newcomer, I lean towards more mundane ideas: in a country where a third of the population lives on less than 25p a day, many have no choice but to dice with death every morning to get to work. If life is sometimes shockingly cheap in India, so are state-subsidised railway tickets. An hour's journey across Bombay by train costs about 12p.

Cheap it may be, but Bombay's railway does not befit the commercial capital of a would-be superpower and some champions of India's economic renaissance question the fatality figures. “Check them, I think you'll find they are too high,” Gurcharan Das, one of India's leading pro-markets commentators, tells me. He is right that India's economic miracle should not be underestimated. Bombay's population is booming (some estimates suggest 400 families are moving here every day), the slums are growing and the trains are heaving because people are being drawn to the city's growing wealth.

But the train death numbers are far worse than Gurcharan can imagine. A day before going to Andheri West, I visited Chetan Khotari, an endearingly manic diamond trader-turned- anti-corruption activist. Chetan, who with his glasses and moustache resembles a sub-continental Groucho Marx, specialises in unearthing hard-to-get information.

Inside his office a safe once used to store gems is crammed with official documents uncovered using India's Freedom of Information Act. I leave with an official breakdown of the causes of the deaths on Bombay's train network over the past five years - and, for a reason that I still can't fathom, a copy of the President of India's electricity bill.

It is from Chetan's documents, obtained from the district railways, that the 16-deaths-a-day figure comes. The lion's share of fatalities, the papers show, are the result of people being mown down while walking on the tracks - too lazy, rushed or tired to climb the packed overhead passes. “Only” about one in six of the 20,700 fatalities recorded since 2003 was the result of a passenger falling from - or being pushed off - an overloaded train, which equates to nearly three people every working day.

On the platform at Andheri, Ibrahim and I discuss the maths. About seven million people use Bombay's railway every day, which I reckon means as a traveller you have one chance in 2.3 million of dying by falling off a train. Ibrahim reckons those odds aren't bad - and that the risk can be mitigated by not sitting on the roof or sticking your head out of the window for a breath of air. I argue that being a virgin traveller must at least double your chances of dying. Moreover, the most dangerous things I've done since being posted to Bombay in January is take ice cubes of dubious provenance in my G&Ts and consume an ill-judged mutton tikka. I paid heavily for both indiscretions.

This in mind, I am not keen to hang out of a train travelling at 40mph. The sentiment is reinforced at the sight of a teenage boy being punched in the head by a middle-aged man when he tries to board what passes for a medium-busy carriage. I am going to choose my moment, I tell Ibrahim. He nods sagely while sidestepping the sprawling teenager.

Waiting, I learn a couple of tricks. Some young lads stand in the middle of the tracks as the train whistles into the station, which means that they can board the train from the side not facing the platform. Innovative, I grant, but not a tactic I'll be using. The most common strategy looks a better bet: the head-down, elbows-out, ramming-speed approach - a technique not unlike that regularly deployed on British transport.

And this is how I find myself, at about 9.55am, finally on the train to Churchgate. Between some stops the ride is rib-crushingly busy and there are some people hanging out of the doors, but deep inside it's no worse than a peak train into London Bridge.

In truth, the worst of the rush hour is past: I've bottled it - but can you blame me? In the corner of the carriage half a dozen old-timers are playing cards. They've been travelling together for years and now invite each other to their children's weddings. Yes, they say, the train has grown busier and something should be done. Has anybody they know died? “Oh, not for weeks.”