Michael McCarthy: The express? More like a crawl to Copenhagen

Sketch: The boss of French railways, SNCF, was prompted to exclaim: "C'est lepremier happening ferroviaire!"

It was worthy. It was green. In fact, it was carbon-neutral. But it was a tad on the slow side.

The Climate Express, a special one-off train put together by the combined efforts of Europe's railways, took environmental campaigners from all over the continent to Copenhagen at the weekend, for the UN climate conference which begins this morning – and your correspondent joined them.

There is no high-speed continuous rail link to the Danish capital from Brussels, where the journey began, so the UIC, the Paris-based International Rail Union, had spent a year organising a special through-service for the 1,133km journey via three different countries (Belgium, Germany and Denmark) with three different rail systems.

Leaving Platform 3 of Brussels Midi station at 9:12am on Saturday, and decorated with environmental logos and a broad green stripe along the side, the Climate Express rattled along via Cologne and Hamburg, and saved huge amounts of carbon compared to travelling by road, or even more if you compared it to flying. But it was 11pm before we pulled into Copenhagen Central.

The intervening 14 hours – the flight would have been less than two – became a cheerful celebration of the growing alliance between environmentalists and railwaymen, who clearly see their interests entwined.

From the rail side there were more Big Cheeses on board than you could wave a red flag at, including the heads of German, Belgian, Spanish, Italian, Japanese and French Railways, as well as Jean-Pierre Loubinoux, who as head of the UIC is officially the world's Top Railway Geezer, while from Britain we had Richard Brown, the green-minded chief executive of Eurostar, who had done his bit for the cause by whisking the British Ecopassengers, as we were politely referred to in all announcements – Dear Ecopassengers! – free of charge to Brussels the night before.

From the environmental side there were campaigners from Friends of the Earth, the Worldwide Fund for Nature (WWF) and various other groups, a bunch of young climate champions brought by the British Council, the green film-makers Franny Armstrong and Lizzie Gillett who made The Age of Stupid about climate change, Betrand Piccard who is trying to fly around the world using only solar power, and luminaries such as Achim Steiner, director of the United Nations Environment Programme and Professor Jean-Pascal van Ypersele, deputy head of the UN's Intergovernmental Panel on Climate Change.

The donnish Professor Van Ypersele symbolised the union of interests by donning a Belgian railwayman's cap and blowing the whistle for the train to depart so loudly that some people jumped and Guillaume Pepy, the boss of French railways, SNCF, was prompted to exclaim: "C'est le premier happening ferroviaire!" ("It's the first railway happening!")

The happening continued with the handing over of the People's Orb, a football-sized symbolic aluminium ball containing electronic petitions with several million signatures demanding action on climate change, to Achim Steiner to take to the conference. It had been lugged from London by Jo Sargent, one the WWF press officers – a heavy responsibility.

If you had anything of the railway buff in you it was very pleasant to be rolling through the north European countryside on what was a great cause, although as the trip was packed with events in special conference carriages, much of the time was spent standing up, and the 14 hours of rockin' and rollin' on the railway left me swaying like an old seadog.

But even my alarming discovery that Danish hotel rooms have sloping floors was not enough to dampen my pride at having ridden the one and only Climate Express to Copenhagen – the greenest train that ever was.