Last New Year's Eve, I was at a party in Dundee. There were kilts, bagpipes and - to compensate - whisky and lots of kissing. My first proper Hogmanay was well worth the trek up from London but the journey home was something else entirely. If I ruled the world I'd transform our trains.

It's not the most horrific story you're ever going to hear, but it's probably quite familiar. We'd reserved seats on one train but couldn't sit in them because the train was too jam-packed even to get aboard. Instead of joining the queue to abuse the station staff, we managed to shove and squeeze on to a later train, and stood for the whole six hours, pressed against other passengers and two swollen bags of rubbish. A guard had earlier given up trying to collect litter and was wisely hiding.

A trip like that made me question visiting Scotland again. I've seen the posters.

I know how much us tourists mean - even whingeing tall ones from London. While losing all sense in my knees and feet, the thoughts of murder weren't eased by knowing how much this trip had cost. Flying home we wouldn't have been usurped from our seats, and it would have been quicker even with time for check-in because of the delays at each station in getting people in and out of the squish.

Old films tantalise us with railways as they should be - full of excitement and romance. Think Eva Marie Saint and Cary Grant insinuating all kinds of filth in the dining car in North by Northwest. Then think of a main line closed all weekend because of engineering.

The £800m refurbishment of St Pancras station in London is one of the largest projects of its kind in decades, and dares suggest the same breadth of ambition and architectural achievement as the building of the railways in the first place. London is also seeing new investment in train lines, with the new Overground and crossrail networks.

I've three proposals to make public transport better for everyone in the UK. First, the trains themselves. Some rail companies have been on about the improvements they've made recently. Their trains are now faster and more regular, and have lovely carpets. There are sockets for plugging in laptops and mobile phones, and they have quiet carriages even in standard class. Yet we're still packed in like sardines.

In March, the government announced yet another subsidy to private rail firms, to provide an additional 1000 carriages to ease overcrowding. The Aslef drivers' union argued that this would do no good. The solution, it said, was to run more trains. It called for more "investment in in-cab signalling which would ensure that there is stopping distance between any two trains on a track - thus allowing more, safer, rail traffic". That's where subsidies should go.

Being 6ft 3in, I'd quite like trains where my knees weren't pressed against the seat in front. And some of these gleaming new trains don't provide luggage space that fits, you know, actual luggage. As the rail firms see it, the more people you can cram into a carriage, the more tickets you can sell. But you don't spend a trip like that one from Dundee, wedged into the gaps between people's suitcases, thinking how you must do this again.

Ironically, government subsidies were significantly lower before privatisation, and in its latter days the state-owned British Rail was considered to be one of the most efficient railway operators in the world. So I'd re-nationalise the trains.

I'd also stop the constant announcements from the driver and the buffet car. You don't really need to list all the hot and cold drinks as we pull out of every station. And, obviously, I'd make train fares cheaper than the same journey by plane.

Secondly, as well as the trains themselves, it would help if there were lines to run them on. Trying to visit my parents a fortnight ago, all three lines to get me there turned out to be closed that Sunday. I'm sure you can hear them snigger as they say "sorry for any inconvenience". Again, it's more expensive to send the engineers out at night, and I'm sure the railways are suffering from decades of penny-pinching. But if people can't use the trains at weekends, there's less revenue from tickets to spend on repairs.

And thirdly, and perhaps most importantly, I'd try to reopen as many of the branch lines as possible. Dr Beeching closed a great wealth of lines, and stranded whole communities, on the basis of these lines running at a loss. So how would they pay for themselves now? Initial subsidies would encourage businesses to use the train lines rather than lorries for long-distance haulage. They'd then use lorries locally, to ship stuff from the branch line to their shops and customers. That would make the roads less busy, and businesses would share the costs with passengers.

A greater wealth of railway lines in smaller towns and the countryside would also mean less excuse for cars and domestic flights. On that basis, there could be congestion charges in other towns and cities, encouraging people to use trains whenever they could, with the money going to the train lines. And less traffic on the roads wouldn't just mean less pollution and fewer kids with bronchitis. It would also make driving, when you did drive, that much more enjoyable.

Finally, since I'd be the ruler of the world, any train I went on would let me go up the front with the driver and maybe work some of the controls. Especially the whistle for going into tunnels. Whoo-whooooo!

  • Simon Guerrier's novel Doctor Who: The Pirate Loop is published by BBC Books on December 27.
  • What do you think? Comment below or e-mail (with the subject line Think Tank). We'll bring you the best responses later this week.

  • And if you have a radical idea you'd like us to consider, e-mail an outline to the same address.