The landmark wooden roller coaster at Shanghai's new amusement park stopped seven times yesterday - the park's first day of operation, restricted to members and privileged customers.

The breakdowns and dozens of other troubles at Happy Valley in Shanghai's Songjiang District yesterday has led to the delay of the park's official opening.

Some people were stuck by the park's star free-fall ride midair for minutes. Technicians later found out the short-circuit was caused by a metal pen cap dropped from a visitor's pocket.

Countless small accidents, hours of waiting, bad food and poor facilities sparked outrage among thousands of visitors, many of whom had waited for hours in the rain before the gate opened.

However, what the park offered were a third of its rides and a strong smell of paint as much of the park is yet to be finished.

A sign board fell on three visitors's head, but the park's first aid centre has not been completed yet.

The park's doctor ran from one spot to another to treat the injured.

Some visitors lost their temper and argued with park staff.

Visitor Chen Yating complained she had spent hours waiting for the free-fall ride, only to find it had stopped operating for safety reason.

A group of three men had to wait four hours for the two-minute roller-coaster ride.

The park operator said between 9,000 and 10,000 people - a third of its capacity - visited the park yesterday, but it was far beyond the capacity for its facilities and all the three fast food outlets.

Visitor Xia Yan said she spent two hours waiting to buy KFC - about the same time she spent on park rides.

OCT Enterprises Co, which also operates Happy Valley amusement parks in Chengdu, Beijing and Shenzhen, has decided to cancel today's trial and delay the official opening until August 16, citing Typhoon Morakot that's supposed to hit the city today as their reasoning.