LHASA, Tibet  They come by new high-altitude trains, four a day, cruising 1,200 miles past snow-capped mountains. And they come by military truck convoy, lumbering across the roof of the world.

Han Chinese workers, investors, merchants, teachers and soldiers are pouring into remote Tibet. After the violence that ravaged this region in 2008, China’s aim is to make Tibet wealthier  and more Chinese.

Chinese leaders see development, along with an enhanced security presence, as the key to pacifying the Buddhist region. The central government invested $3 billion in the Tibet Autonomous Region last year, a 31 percent increase over 2008. Tibet’s gross domestic product is growing at a 12 percent annual rate, faster than the robust Chinese national average.

Simple restaurants located in white prefabricated houses and run by ethnic Han businesspeople who take the train have sprung up even at a remote lake north of Lhasa. About 1.2 million rural Tibetans, nearly 40 percent of the region’s population, have been moved into new residences under a “comfortable housing” program. And officials promise to increase tourism fourfold by 2020, to 20 million visitors a year.