appConfigEntityId

bodyType

customContents

entityId

entityUuid

articlePageQuery

filter

article

articleBaseAdvertisingInfoArticle

articleListArticle

articleSeoArticle

hooksArticleAcknowledgementGateOverlayArticle

hooksTrackPageViewArticle

hooksContentInterestArticle

articleLinkingDataContent

hooksAmpRedirectArticle

articleSchemaContent

hooksArticlePageAdvertisementConfigArticle

liveArticle

appConfig

advertZone

sentiment

contentLock

topics

types

sections

paywallTypes

createdDate

publishedDate

sponsorType

urlAlias

moreOnThisArticles

sectionsV2

commentCount

authorLocations

authors

corrections

displaySlideShow

multimediaEmbed

printHeadline

seriesContainer

articleSpeeches

socialHeadline

headline

images

flag

firstTopic

glossary

flattenTypeIds

image

relatedLinks

relatedNewsletters

__typename

sponsor

pdfFiles

seriesReverseOrder

series

disableOffPlatformContent

published

updatedDate

summary

subHeadline

body

keywords

readingTime

customTimezone

liveContents

json

Martin Wong

The improper operation of service brakes on the Ngong Ping 360  cable car during an unnecessary test run caused an empty gondola to fall 50 metres off the ropeway on to a hillside, according to a final report into the incident.  
The expert panel  said in the report that the fall on June 11, 2007, occurred during a scheduled check of the effectiveness of the braking system by simulating a partial failure of the deceleration mechanism.
'It has to be pointed out that during normal operation of the ropeway, the possibility of simultaneous failure of both groups of service brakes is extremely remote,' it said.  
It noted that Leitner, the Austrian ropeway manufacturer, reported that in  more than 130 similar ropeway systems it had installed, there had been no such double failure.
 'The brake test to simulate the failure of  both service brakes  ... is not necessary, and should not be allowed,' the report said.    
 According to the design, the failure of the modulation control of any one group of the service brakes would automatically trigger an alarm  and stop the ropeway by initiating a controlled deceleration.
The panel noted that the testing had caused the ropeway to decelerate in a way that exceeded the limit stipulated by the manufacturer.
'The deceleration  caused the track rope and the hauling rope to swing vertically and caused cabin No21 to derail,' it said.  
It was the panel's view  that even after the carriage had partially come off, it  might not have fallen off had staff been deployed at  key locations to keep an eye on the swinging of the cabins and  ropes. 
The fall could have been prevented if care and diligence had been exercised in examining the deceleration rate, it said.  
The report was released a day after the government dropped  negligence charges against Ngong Ping 360's former managing director Bill Calderwood  and assistant maintenance manager Thomas Li Kit-loi.  The government said it felt that a prolonged trial would not be in the public interest. 
An edited version of the report, which said the operator had acted poorly in managing and maintaining the system, was issued in September 2007.
Although no one was injured in the accident, the cable-car service was suspended for about six months. 
Commenting on the report yesterday, Morris Cheung Siu-wa,  managing director of Ngong Ping 360, said the company was determined to improve safety and operation. 
'We have reinforced our training scheme and improved our company culture ... We have made zero failure  our goal. And even if there is failure, we will try to solve it within the shortest period of time,' he said.
'In 2008, the reliability rate of the cable car was 99 per cent. There were 1.6 million passengers.'  
Stressing that safety was a prime concern,  he said the service would be suspended for five days every year for an examination and  a three-week maintenance of the ropeway  would be conducted mid-year.
Taking the plunge
Key points from the report into the cable car accident
Conclusions
Improper use of brakes during annual test brought ropeway to a halt too quickly
Rapid deceleration made both ropes swing vertically and derailed gondola
Cabin fell after collision between misaligned cabin carriage and roller wheels
Incident could have been avoided by, for example, deploying staff to observe cabin movement
Recommendations
Ropeway operators and maintenance staff should take part in refresher courses
Procedures and instructions should be put in place for annual tests
Staff must check for possible derailments before restarting system
Entire ropeway should be observed during brake tests
SOURCE: ELECTRICAL AND MECHANICAL SERVICES DEPARTMENT



Cable car accident blamed on brake test