But for many tour planners and tourists, it has been anything but a vacation. Tickets are scarce. Passengers may unwillingly get stuck with hard seats for an overnight trip. And some travelers in fact say a Tibet trip made them ill, due to altitude sickness.

Some travel companies which had looked forward to promoting the train are turning their backs on it. With no tickets, there was no point to promote the destination, they said.

"We prepared several travel packages for the railway trip, but now it seems a no-go," said Lu Guanliang, general manager of the Shanghai Old Chenghuang Temple Travel Agency.

Another local travel agency that specializes in Tibet travel, said small tour groups have a better chance to get on the train.

"I tell my clients that they may have to postpone their schedule," said Wang Jiping, general manager of the Shanghai Odyssey Travel Agency.

To get sleeper tickets is a tough mission, said the manager. The agency sent off three groups since July 16, half of the travelers had to take hard seats from Xining, Qinghai Province, to Lhasa, capital city of Tibet. The overnight trip takes about 27 hours.

Tourists like Huang Yumao, 60, canceled his Tibet trip on July 16, when he thought he would end up with a hard seat.

To solve the ticket problem, Wang has employees stationed in Xining to buy tickets.

"I can't guarantee my tours leave on time if my employees didn't line up two days in advance at the ticket booth," said Wang. "Usually you need to line up a couple days in advance to have the tickets."

On July 3 when the first Beijing-Lhasa train stopped at its Lhasa terminal, the hotel occupancy in Lhasa peaked at 97 percent that night. However, local authority announced a cap at 2,300 tourists daily to the Potala Palace to protect the Tibetan religious landmark built in the 7th century. About 1,300 tickets are sold to tour groups, and the rest to individual travelers.

"Therefore, it's now better to buy tickets one day ahead," Liu Bihong, spokeswoman at the Tibetan Tourism Bureau Shanghai Office, said.

The latest complaints came from tourists who suffered from acute altitude sickness on the plateau. Some asked for reimbursements from insurance companies, but came back disappointed.

Jenny An, a local saleswoman, was hospitalized on a trip to Tibet due to acute altitude sickness, and billed for more than 2,000 yuan. She was turned down by her insurance company. A company spokesman said altitude sickness is not an accidental injury.