MADRAS, India -- Railway lines fulfill dreams -- at least in modern times. But the one about to link central Tibet with China threatens to dash hopes.

When passenger trains begin running on this stretch in 2007, hundreds of Han Chinese will immigrate to Tibet. Tibetans are already in a minority in the cities. This new influx will just swamp them. And this is precisely what Beijing wants: a less gruesome form of ethnic cleansing.

The railway line is merely one of the many threats that the Tibetans face. Since their spiritual leader, the Dalai Lama, escaped to India with about 80,000 followers in 1959 after China put down a rebellion in Tibet, this simple, largely pastoral race has been in deep despair.