'THE DEBATE about transport should not be left to experts or to engineers', suggested Dr Anna Kajumulo Tibaijuka, Executive Director of the UN-Habitat urban development programme on May 24, signing a memorandum of association with the International Association of Public Transport.

The theme of sustainable mobility ran right through UITP's 57th World Congress in Helsinki on May 21-24. 'Public transport is today recognised as a civilisation issue that goes far beyond the mere transportation question', said UITP President Roberto Cavalieri. 'It is a critical element in the major societal debates such as climate change, energy efficiency or poverty alleviation.'

During the week, Siemens unveiled a report on 'Megacity Challenges' by MRC McLean Hazel, which put transport as one of the top concerns for stakeholders in 25 of the world's biggest cities.

And one of the biggest issues facing tomorrow's transport operators will be energy. Giving the keynote address on May 21, the President of the Foundation on Economic Trends Jeremy Rifkin warned that the decline in global oil reserves over the next 20 years would leave operators increasingly reliant on alternative energy sources.

Rifkin favours the rapid development of hydrogen fuel cells, but hydrogen is only a 'vector' to transfer energy from the generator to the point of consumption, and is barely 25% as efficient as an all-electric transmission. So as an industry we should be focusing on electrification.

It is interesting to compare the differ-ing attitudes prevailing in the eastern and western hemispheres. In the east, where rail policy, at least, is still largely state controlled, main line electrification is already widespread or continuing apace. But in the west the largely private sector railways have yet to grapple with the practical and commercial challenges of wiring long routes in difficult terrain.

Fuel cells may offer scope for self-propelled vehicles, on routes where the traffic does not justify the capital cost of electrification. But fuel cell development is still in its early days, and there are already other ways to improve rail's energy efficiency. This issue includes features on regenerative braking and on-board energy storage, for example.

Alternative fuels are under consider-ation too, although Jack Short, Secretary-General of the International Transport Forum, expressed concern on June 12 that 'few biofuels seem to offer much in the way of climate protection or oil security, and are a very expensive way of addressing these concerns'.

Virgin Trains and Bombardier put the UK's first biodiesel-fuelled trainset into revenue service on June 7, as part of a co-ordinated national programme. One of Virgin Cross-Country's Voyager DEMUs has been adapted to use a blend of 20% biofuel for a six-month trial. But we note that the four-engined train spent half of its inaugural journey running under 25 kV wires - as do many Voyagers every day.

When we asked Bombardier if it would be feasible to feed the DEMU's electric transmission from the overhead line, we learned that this was indeed under consideration the company is already supplying electro-diesel multiple-units in France. Watch this space.