All aboard Spain's excess express

The Al Andalus Expreso is the biggest grown-ups' toy in the world, a toy you can actually live inside - with a drinks licence.

Built in 1929, this train is a fully functioning museum piece: there are restaurant cars with silver service dining, a games carriage with comfy leather chairs for fierce afternoon bridge and a lounge where musicians play at cocktail hour. Best of all, there's a modern shower car - the train may be redolent of the belle epoque, but you don't have to be.

With 80-odd passengers, the journey is a sociable event. Some were German but, like traveller's stomach, you can only take reasonable steps to protect yourself. Most were of a generation who dressed for dinner and I thought I was in for a quiet week. I thought wrong. They dressed for dinner as a decoy.

Retired in the sense that L Ron Hubbard is a Reverend, this lot were ready to rave. Phil and Judy bounded up to the bar and demanded a Castlemaine XXXX, 'the only beer us Aussies can spell'. Sixtysomething Bob and Marge were gearing up to backpack in Peru. The affable Pat from Wapping had crooked her knee - driving a forklift truck.

I got talking to Enid and her husband Bert the steeplejack. 'Drinking used to be rife among steeplejacks,' he said, worryingly, 'but we've managed to eradicate it.'

The other passengers were no coach party. 'We've got to the stage where we don't even bother nicking the soap unless it's Roget & Gallet,' said Doris mischievously. Slightly nervous, I declined another enormous G 'n' T and slunk off to my cabin where, appropriately, slippers and dressing gown awaited me.

My cabin was very cute - sculpted wooden doors hid a beautiful vanity unit, secret draw-ers pulled out of walls - although if I'd been strangled in my bed, Poirot would have been looking for a short man, or a tall man with a bump on his head. According to the brochure, being on a train leads to 'a more intense, interesting inter-action among travellers'. I'll say. Bring anyone back to your cabin and you'd have to get 'interesting' or get a chiropractor.

The Expreso hissed into motion and we set off from Seville. It was a strange sensation to be cleaning my teeth and feel my bathroom lurch to the left, at least on a week night. Soon we were speeding across Andalucia's plains, past traditional ramshackle farmhouses and their traditional ramshackle Skodas.

Our first stop was Cordoba, home of Europe's most prestigious mosque outside North-West London. The ravers and I had a 100-course dinner and blundered back to the station where our hotel was waiting on the tracks. We climbed into the polished wood carriages, eyed bitterly by commuters waiting for the 00.05 to the 'burbs.

That night as I lay in bed, the train shunted off the buffers and clattered through the darkness. It took some getting used to: I kept lurching awake, convinced I'd fallen asleep on the Tube and arrived in Harrow and Wealdstone dribbling.

The next morning I woke to find myself comfortably tucked up on platform one, Granada. Everyone was up earlier than me to claim their champagne breakfast. Time meant nothing to these people. I wanted to tell them to slow down, but then I remembered I didn't have a heart condition.

Over breakfast, the stewardesses told us stories about Christopher Columbus, who was apparently paid in jewellery - Queen Isabella was broke after Spain's ten-year war against the occupying Moors and actually handed over her own necklaces. How extraordinary, I thought: a royal paying for something.

Granada is most famous for the Alhambra, a Moorish fort carved in red stone, and its Generalife Gardens, heavy with the smell of jasmine, orange trees and, er, other stuff. I don't know, they looked like plants to me. As the morning wore on, I resolved never to go on guided walks with anyone over 60; the trouble with older people is they know things, so they argue with the guides, delaying the crucial break for lunch.

The fort had bedroom windows with screens carved into stone lace that worked like two-way mirrors, so that only the sultan could see the ravishing beauty of his 70 concubines. Then again, he'd probably had arranged marriages and got the whole lot sight unseen, so the screens meant that only he knew the daily disappointment of such riches. But 70 concubines are 70 concubines; when the sultan lost the ten-year war I suspect that, to get over the agony, he had an early night.

The Alhambra had been decorated by the Moors in geometric design because Islam does not permit the reproduction of people or animals.

You wondered if, after a lifetime painting octagons, an artist thought: 'Stuff it, I'm going to do a cat.' And whether in the morning when his work was seen, mothers shielded their children's eyes, before piously stoning the artist to death.

Then after all this geometry, I saw no fewer than 12 carved animals - the famous Alhambra 'lions'. My guide explained this blasphemous aberration was a gift to the sultan from a Jewish friend who presented them as representations of the 12 tribes of Israel, and the sultan had so many Jewish ministers he was too scared to leave the lions out for the binmen.

Transparent nonsense: they looked nothing like lions, they were clearly prototypes of those porcelain dogs you buy in sofa warehouses on ring roads. The real story was obvious:

'Aren't you ready yet? We've got to be at the sultan's at eight.'

'Did we get him anything?' 'You were - oh, we'll pick up a bottle of wine.'

'He's a Muslim! How many times . . .'

'Look, we'll give him that dog your mother gave us. What time does World of Leather close? We can get him a set.'

'And what? Tell him they're the 12 tribes of Israel?'

During cocktail hour on board, Bert told me about his other train journeys. 'This is nothing like the Trans-Siberian Express,' he said accurately. 'There was a hole in the floor for a toilet, and washing meant three stainless steel bowls where everyone could see you.' Very different from the Al Andalus Expreso, which had green marble sinks with goldfish taps I couldn't work.

The next morning was a grimly early call, and I considered hiding under my bunk from the pensioners. At that hour, you appreciate living on the train - with your hotel following you, you never have to repack your bags.

At Hotel La Bobadilla in Salinas, where we stopped for lunch, we witnessed a strange display from our host. He took us earnestly into a side room, keen to demonstrate his pride and joy, a vast church piano. 'Now that's what I call an enormous organ,' noted the seniors as our host performed self-consciously - he obviously didn't show it to strangers very often.

Ronda was the highlight of the trip - the spectacular walled city straddling a gorge full of doves and kestrels. The bridge was built by a mayor with funds from an innovative public drunkenness fine, something that would definitely fund the Channel Tunnel-Edinburgh rail link.

Ronda is home to the oldest bull-ring in Spain, location of Hemingway's Death In The Afternoon, and Orson Welles's favourite place to get drunk and shout at cows. The senior citizens led the way via more welcome sherry to a 1,000-course lunch with buckets of wine. I wanted dialysis. My head felt like Ernest Hemingway had washed his beard in it.

The late dinners and early starts were doing me in, but the seniors weren't bothered at all; they simply took 'disco naps', ready for more partying. I wouldn't have been surprised if one of them had brought their own strobe light.

On Thursday, we had another horribly early breakfast before being shipped to the Spanish Riding School for a 'horse ballet', about as stupid a concept as seal stand-up or chicken panto - everyone knows chickens never remember their cues.

The show was called 'Como bail-lan los caballos', or 'how the horses dance', to which the answer is 'badly'. They didn't have natural rhythm, not even the black ones.

At best they appeared to be taking off Mr Humphries in Are You Being Served?, the first time I've been given the come-on by a horse, and I soon regretted sitting at the front: I discovered rather too much about 'how the horses digest'.

Dinner was a traditional Andalucian tomato soup garnished with chopped bacon and boiled eggs. 'It's breakfast recycled!' bellowed Aussie Phil lustily, ordering more Rioja. I told them I was going to get a Scrabble board and went to bed before someone suggested strip poker. I wasn't in as good shape as these people.

My cabin was still great fun, at least when I kept it neat - one towel on the floor and it descended into primeval chaos. Mike and Doris, however, were masters of their domain.

'I've got it sorted,' announced Mike. 'I slide off the top bunk into my trousers like Wallace out of Wallace & Gromit.'

At cocktail hour I got talking to the elegant Connecticut sailors Cheryl and Rene. 'We were once moored off the coast of Norway,' reminisced Rene, 'and we sent a launch over to King Olaf's yacht with an invitation to cocktails. He turned up at 10.30pm flanked by security officers, completely drunk. He was 85 but he'd just won the boat race and was in a fantastic mood.

'I remember him sitting there crushing huge handfuls of chips against his face so that they all fell down his blazer,' said Cheryl. 'He laughed and laughed. They had to take him home in the end.'

Thank goodness Cheryl didn't have gherkins. He'd probably have laughed himself to death.

I thanked God it was Friday, because the pensioners' reckless hedonism was doing my head in. We were having four glasses of wine at lunch, brandies, sherry every time we walked through a door and cocktails before dinner. They were mildly tiddly. I was paralytic.

I came aboard after a one million-course dinner to find Phil running through the carriages. 'My wife's escaped!' he shouted, disappearing into the games room where Judy was presumably playing sardines with some French octogenarians.

Finally it was the farewell gala dinner. The dining carriages were lit up by flaming baked Alaskas. Surrounded by such surreal luxury, I felt almost sentimental for the rich chemical aromas of Virgin Rail's microwave cheese-burgers. Almost.

The dinner gave way to a marathon dance party. To my alarm, a moustachioed German took the floor with a harmonica.

'Here is a song about zer British,' he said, doing a 'British' walk and lurching into a parody of Chas and Dave. Everyone applauded gaily. So far, so acceptable.

'Und here is a song about zer Spanish!' There followed some oompah flamenco, to much cheering from the Spaniards. I got nervous.

The Spanish retook the floor, advancing in formation to La Bamba. In all, the week was a glamorous knees-up for people determined to make the most of retirement. Heaven knows what high jinks will happen on board during the Al Andalus's November golfing tour; the combination of train spirit and no-holds-barred golf craziness doesn't bear thinking about.

I don't think I'll be there: I can't take the pace.

Getting there
Mundi Color (020 7828 6021) offers holidays on board the Al Andalus Expreso from £1,277. This includes return flights from London with Iberia, one night B&B in Seville, five nights' full board on the train, excursions and transfers. Holidays from Manchester cost from £1,327 and from Glasgow £1,342.