Johannesburg — TRANSPORT Minister Sibusiso Ndebele this week signed a wide-ranging agreement with the Chinese railways minister to foster co-operation between the two countries.

Speculation is rife that Ndebele's longstanding dream of a high-speed rail link between Johannesburg and Durban is about to become a reality, courtesy of this new relationship.

Ndebele observed as early as September 2006, when he was KwaZulu-Natal premier, that trains travelling faster than 200km/h could cut journey times between the two cities from 12 to just three hours. He found fresh inspiration early this year in the high-speed rail link under construction between Shanghai and Beijing. There are four broad areas of concern about the proposal.

First, megaprojects have created political turmoil in recent years. The arms deal and Eskom's current power generation programme have brought waste and the alleged diversion of public funds into African National Congress (ANC) factional war chests. Cynics complain that high-speed rail is merely a ruse to divert funds to KwaZulu-Natal's ANC-aligned political and business elites.

Second, investment on this scale will destabilise politics and planning in Durban. The scramble for land close to potential station sites has been under way for some time, and we can now expect a decade of planning-regulation manipulations. The South African National Taxi Council is already demanding a share of revenue in return for its acquiescence.

Third, the project will deepen the involvement of the Chinese communist party in domestic politics, most worryingly in the factional politics of the ANC itself. It is fashionable in parts of the liberation movement to view China as a model partner, free from western obsessions with bourgeois democracy and labour rights. It seems unwise, however, to build indebtedness to an undemocratic and potentially unstable state in pursuit of SA's mineral resources.

Fourth, the whole enterprise makes no economic sense. Such rail systems pay in areas of high population density, when airports cannot grow, existing rail capacity cannot be expanded, and where journey times between major economic centres are at a premium. None of these factors holds in the proposed link. Population densities are low and travellers are well served by expensive new airports and feeder systems such as Gautrain.

One early estimate of the cost of a high-speed link is 30b n or R220b n. Such systems are expensive because they require dedicated tracks, low grading, few stops and no level crossings. Levelling and tunnelling, notably in the Drakensberg , adds uncertainty to the mix. SA might directly pay 40% of the costs, with the balance covered by loans from Chinese state-owned banks. SA would therefore employ idle Chinese engineers during that country's economic slowdown, while acquiring long-term liabilities to politically controlled Chinese banks.

Brainy Trade and Industry Minister Rob Davies , a boys-with-toys economist, almost certainly loves space rockets and trains. This egghead may well claim there are "positive externalities" and Erwinian "offsets" underlying the deal that only he is clever enough to understand. Others desperate to justify the project will argue that the line can also carry freight. Such mixed-traffic systems, however, are hard to build and maintain, and track sharing would substantially increase passenger journey times.

Deputy Transport Minister Jeremy Cronin, the deputy general secretary of the South African Communist Party, has a decade of experience in this field as a former chairman of Parliament's transport portfolio committee. He is aware existing freight services could be upgraded quite cheaply to speeds of almost 150km/h, cutting travel times to five hours. Such a service could even have a reliable passenger component to relieve congestion on the roads.

Will Cronin tell the public the truth about his department's feasibility study? Or will ANC factional politics and pressure from special interests result in this immensely expensive white elephant forcing its way through the Cabinet system to the detriment of the citizens Cronin used to serve?

Butler teaches politics at Wits University.