An investigation found no signs of sabotage in Wednesday's train accident in Taiwan, according to a report released during a press conference on Thursday by the forestry department under the island's agricultural authority.

Injured Chinese mainland tourists receive medical treatment in a local hospital in Taiwan on April, 27, 2011. A small train overturned in Taiwan's Ali Mountain area on April 28, killing five tourists from the mainland and injuring more than 100 others. [Xinhua photo]

A small train overturned in Taiwan's Ali Mountain area on Wednesday, April 28, killing five tourists from the mainland and injuring more than 100 others.

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According to sources with the Chiayi fire department, a large tree branch broke and fell on the railway. The branch hit the train's rear carriage and caused several other carriages to overturn.

A panel consisting of four forestry experts conducted the investigation, according to the report. The panel found that that the branch fell because of structural damage to the tree and was not the work of saboteurs, the report said.

Local regulations state that small railways should be located at least five meters from surrounding trees. The railway where the accident occurred is eight meters from the nearest treeline, said Chen Wu-hsiung, head of Taiwan's agricultural authority, at the press conference.

However, the island's forestry and railway authorities will continue to investigate the incident and make recommendations for improving railway safety standards, Chen said.

The train's drivers were found to have valid driving licenses.

The forestry department suspended usage of the railway for a week in order to conduct their investigation.