Development through infrastructure has worked in China, but China is not only an authoritarian state; it is also a managerial or technocratic one, in which the ruling party marshals the nation’s energies and capital in the name of development and stability. Angola, on the other hand, is a semifunctional oligarchy. Jaime and his fellow technocrats may know very well what they are doing, but even Angola’s biggest boosters concede that the real power lies with President dos Santos and his circle. The big public-works projects, for example, are now being directed not by the ministries but by Gen. Manuel Hélder Dias, a close associate of the president. This subject is so sensitive that when I raised it, Jaime made me turn off my tape recorder. And President dos Santos shows no signs of releasing the grip on power he has held for 27 years. He has postponed elections again and again. The ruling M.P.L.A. (Movement for the Liberation of Angola) and the state are virtually one; even their flags are almost identical. It’s hard to feel confident about the uses to which the national bounty will be put so long as power and wealth are concentrated in one man and his entourage.

One morning I left Kuito and headed east once again in a last-ditch effort to locate the elusive Chinese railway workers. Sales Duarte, then a project manager with CARE who was working as my guide and translator, a photographer and I drove 80 miles over pitted roads to Kwanza, a small town on the banks of the Kwanza River. No sign of the Chinese. The road ended at a railway bridge said to have been dynamited by South African mercenaries in 1989. The bridge must have measured about 150 yards long; at its center, which now lay in the water, bare-breasted village women washed themselves and their babies. Much stranger, though, was the sight of a battered blue Toyota 4 by 4 with its tires on the tracks and its front bumper submerged in the water. Perhaps it had been sitting there since 1989.

The bridge provided the only connection between the towns along the railway line, and quite a lot of traffic was moving in either direction. A column of bicyclists passed by with rolled-up mattresses strapped to the backs of their bikes. They had come all the way from Kuito, where mattresses were cheaper than in the local market, and were continuing on to Kuembe, the next big town, a distance of about 100 miles. An official from the Ministry of Health was taking a pack of vaccines by motorbike from Kuito to Kuembe.

Just as I reached the eastern side of the bridge I heard a tremendous roar — the Toyota was fishtailing wildly at the base of the bridge. It bucked forward and then slipped back. Only then did I discover that this jalopy, with bales of material and a live chicken in the back, was in fact the Kuembe-Kuito taxi service. The driver, Anacleto Kakande, said that he made the round trip twice a week. Somehow, four times a week he would navigate the bent railroad tracks, the shattered bed, the logs, the foot-high water. The five women, with five babies, waiting patiently at the western edge of the bridge were his fares; they said they were charged 1,500 kwanzas — about $19 — for the trip. It was only then that I fully understood how the terribly abstract word “infrastructure” could come to feel like life itself. For 15 years, the traders and farmers of this region had lived with no other means of crossing from one side of the Kwanza River to the other. (Why a ferry service hadn’t been developed, I have no idea.) They had improvised heroically, but at an absurd cost in time and effort. If those Chinese engineers ever got to the bridge, the local economy might really, as Jaime said, jump.

But the Chinese were only a rumor — the very incarnation of a development process imposed from above and answerable to no one. We headed back toward Kuito. As we drove through Kamakupa, a town that, according to a sign, occupies the exact geographical center of Angola, Sales Duarte shouted, “The Chinese!” And there they were, operating derricks in front of the Kamakupa train station. In the fields behind the station we found half a dozen Angolans wrenching nuts and bolts from the train tracks and two Chinese employees, in clean dress shirts, advising them in pidgin Portuguese. Guards from the president’s own security service watched over them. We approached one of the Angolan workers, who complained that he was earning only 200 kwanzas a day — $2.50 — and added bitterly, “and they don’t even give us lunch.”

Out front, we found the boss, a young Chinese man who spoke excellent Portuguese and introduced himself as “Eddy.” He and his team of 12 Chinese nationals worked for the National Railway Company of Hong Kong; the bulk of the workers on the project were Angolan. The tracks, Eddy explained, were unusable, so they were being separated in order to be torn from the ground. They would go to work on the bridge as soon as the equipment arrived from China. “We’re responsible for repairing the railroad all the way to Moxico,” he said — a distance of 55 miles. How long would it take? Maybe three years, maybe five. And as he spoke, an immense splintering noise shattered the late-afternoon torpor of Kamakupa, as the derrick operator knocked over a tree that marred the perfect, smooth surface he was creating. Here, at last, was the wreckage of creation.

The Chinese premier, Wen Jiabao, visited Angola over the summer and announced that China had extended another $2 billion to Angola, on top of $1 billion announced a few months earlier and the original $2 billion from 2004. But Angola was only one stop on Wen’s seven-nation tour of Africa. He also announced a series of trade agreements with the Congo Republic, a country just beginning to exploit its oil deposits. China is now one of Africa’s largest customers not only for oil but also for timber, minerals, cotton and other natural resources. China in turn has flooded Africa with cheap consumer goods. The I.M.F. forecasts that China’s trade with Africa will top $50 billion this year and could reach $100 billion by 2010. Over the last five years, sub-Saharan Africa’s growth rate has almost doubled, to 5.8 percent from 3 percent; economists attribute much of the increase to trade with China and other Asian countries.