don't need to join a travel team. but u have to apply for a permit if u are a foreigner. u can apply for permit in Golmud. there are many bus from Golmud to Lhasa.

1, no train in Lhasa, but u can arrive to Ge'ermu (one city near Tibet), where you can take a bus or hire a jeep to lhasa (1200 km, about 2 days). 2, u must join a travel group if u want to visit Tibet. 3， is the office website for visiting Tibet, which maybe helpful to u.

from chengdu, there is just flight or bus to Lhasa, no railways yet。

As kowch said,there is no train from Chengdu to Lhasa. If u don't wanna make airplane,u must take the car.But it is so danger.

I think u must get the wrong information. There isn't any train from Chengdu to Lhasa , there isn't a railway from Chengdu to Lhasa. No railways reach Lhasa. But there are three highway to Lhasa, the Qingzhang highway, The Chuanzang Highway and the Tianzang highway. And there isn't any directly bus from Chengdu to Lhasa. You can hire a jeep from Lhasa to Zhangmu, the border to Nepal. and then Pass the border, then hire another jeep from Zhangmu to Kodari, the customs of Nepal. then from Kodari take a jeep to Kathmandu.

lhasa=lasa = 拉萨市

Where is Lhasa?