IT WAS a little after 8pm and the metallic silver giant that is the Sunset Limited transcontinental train lumbered into the station in the little West Texan town of Alpine. I showed the conductor my ticket and he led me to a window seat, looking out towards the distant mountains, the Mexican border and Chihuaua, except someone had left a couple of books on my seat.

I moved them to the adjoining seat and after a while a tall, rather handsome young African-American appeared, looked down at the books and asked “Did you move my property?”

I explained that they had been on my seat and I did not know where the owner was. “You had no right to touch my property,” the newcomer informed me. “And it is my seat,” he added.

I explained that the conductor had shown me to that seat.

After my new acquaintance repeated several more times that I had no right to touch his property and repeated his claim to the seat, I proposed he get the conductor to adjudicate. He suggested that I should get the conductor. I pointed out that I was not only in possession of a reservation, I was also, crucially, in possession of the seat.

To which he responded, loud enough to let the whole carriage hear: “I am a marine. I was with the marines in Iraq.”

Now, my patience was wearing just a little thin. “I was in the British Army and I was with 45 Commando and special forces in the jungles of Central America,” I told him, before adding: “And that is equally irrelevant when it comes to the seat.”

It is technically true that I was with special forces. And off he went to look for the conductor.

The railroads opened up an entire continent and with them came adventure, drama and violence – and there was certainly a little drama in this little misunderstanding over the seat.

It used to take months to get from the East Coast to California, if you got there at all. Now you could do it by train in a couple of days.

I know there is a legion of train enthusiasts in the UK, but trains here did not open up a continent in the same way. And for me the interest is not in locomotives and engineering, but in the romance, legend and mythology of the Iron Horse, pushing its way across desert, mountain and swamp. This is the stuff of American folklore, songs, books and the western movies I grew up on – railroads and trains play key roles in High Noon, How the West Was Won, Once Upon a Time in the West and of course Blazing Saddles. And I wanted to take the ride.

But which ride? Amtrak has over 40 routes, with such evocative names as Empire Builder and Texas Eagle. I opted for The Sunset Limited, which takes two days to cover 1,995 miles from Los Angeles to New Orleans. It is not fast and frequently falls behind schedule – in the US passenger trains give way to freight.

I wanted to stop off and see a little of Texas. I considered a combination of El Paso and San Antonio or Galveston, which is just a 90-minute bus ride from Houston. I decided to get off in Alpine and drive down to the Big Bend National Park on the Mexican border. But first I had a day to kill in Los Angeles before my 10 pm departure time.

LA has acquired an extensive underground train system since my last visit and that is not the only change. I used to love the faded grandeur around Hollywood and Highland. The exotic Chinese Theatre, where they hosted big premieres, is still there. And the old Roosevelt Theatre, with its ornate painted ceiling and wood-panelled bar, is much as it was when I used it as a setting in my novel The Man in the Seventh Row. It hosted the first Oscars in 1929. But they have torn down almost everything else to build the Dolby Theatre, the new Oscar venue, and a multi-storey shopping development.

In the 1980s and 90s I stayed in a little low-rise hotel called Orchid Suites, behind the Chinese Theatre. The hotel and its tiny pool was my retreat when I spent a week in LA when Braveheart won the Oscar. I assumed Orchid Suites had vanished beneath the new development, but it is still there, in Dolby's shadow, and only the prices have changed.

Back in the day, tourists avoided this area. But the pimps and sex shops have gone and the Japanese now throng round the Chinese. I wonder how many realise the giant arch and big stone elephants in the new development are copied from DW Griffith's silent classic Babylon?

Sunset Limited leaves LA at 10pm, thrice weekly, so it is dark as we roll through Palm Springs, Yuma – another town whose train service figured prominently in a classic western, and Maricopa, stop-off for Phoenix. The names resonate in a way that By the Time I Get to Broxburn just doesn’t. I slumbered as the train lumbered.

There is a dining car, with liveried waiters and an observation car, providing an ever-changing desert panorama. I got off briefly to be photographed beside the El Paso station sign, but did not fall in love with a Mexican girl. This is like riding through the Great American Songbook.

The train runs along the border and at this point there is already a fence dividing El Paso from Ciudad Juarez. Seen from a plane you might think they were one city, but looking out of a train window the poverty on the Mexican side is fairly obvious. Despite their proximity, El Paso has one of the lowest crime rates in the US and Ciudad Juarez has one of the highest murder rates in the world.

There was much consternation on the train because it was terminating in San Antonio because of flooding. But I was getting off before that and driving down to the Big Bend National Park, one of America’s best kept secrets, a sprawling wilderness, with warning signs about bears and mountain lions and trails and scenery that inspired one guy I met to spontaneously turn and propose to his girlfriend. But I wrote about Big Bend and Terlingua ghost town in a previous piece, so I will return to Alpine, the train and the Marine.

Alpine exists only because of the railroad. Those of Northern European descent settled north of the railroad and Mexicans, employed initially to lay the line, built adobe houses on the other side of the tracks. I had a beer in Harry’s Bar and the owner wound up driving me to an unpretentious little Mexican cantina on the south side, where I had green chilli enchiladas before walking back to the station.

After the initial disagreement with the Marine, he returned with the conductor, who checked my ticket, exchanged a few quiet words with the Marine and walked off down the aisle. The Marine announced to the whole carriage that the conductor was “an asshole” and followed in the conductor’s wake. That was the last I saw of him, though the possibility of a further meeting did weigh on my mind over the next 24 hours. It was the only real disagreement I had with anyone during a month in the US.

Houston marks a dramatic change from the places that have gone before, a modern business city, with skyscrapers piecing the blue sky. I had just over an hour to quickly make my way to the Chase Tower and its observation floor, which provided an excellent view of the city stretching into the distance.

Fortunately the line beyond San Antonio was open again and desert gradually gave way to what might have been bayous or may have been the remnants of floodwater. Just before New Orleans the train creeps across the Mississippi on the Huey P Long Bridge, at 4.5-miles one of the longest in the US. It is 10 o’clock at night and I have to catch a bus to my air bnb. They used to have a streetcar named Desire of course, but sadly they dug up the tracks and the route is now served by the Number 55 bus.

I had messaged my host with an ETA. I find his house, but he is not in. I knock on the door of the neighbouring house, pointing to my backpack to reassure the occupier that I am not a murderer or rapist – they obviously would not have backpacks. It turns out that not only has the host gone out with friends, but his address is wrong on the listing – he missed the B off after the number and it is round the corner.

But, hey, this is the Big Easy and it all works out in the end. I soak up the atmosphere and history, wandering round the old French Quarter.

I am hypnotised by the mighty river I know so well from the stories of Mark Twain. And I relish surprisingly good ale and unsurprisingly good jazz in the bars of Frenchmen Street, content, journey over, for a short while at least.

TRAVEL NOTES

Amtrak has an excellent website. Advance e-tickets, booked on line for a reserved seat, cost me $102 LA-Alpine and $88 Alpine-New Orleans, about £120 in total for the two-day trip. It is also possible to book a private sleeping compartment. Watch out for luggage restrictions – bags over a certain size need to be checked in and stored in the baggage compartment, and it is not opened at the smaller stations, including Alpine. www.amtrak.com