A KCR train had to be pulled from service yesterday after the frame holding a nylon strap supporting a transformer was itself found to be cracked. The discovery of the 15mm crack led one engineer to question whether the KCR's coach frames are strong enough. Nylon belts have been added to secure major train parts since a mounting device snapped on December 21, leaving a compressor dangling under the train. Speaking after a special board meeting yesterday, KCRC acting chief executive Samuel Lai Man-hay said: 'It is the first time we have found a crack on a pivotal point ... but 15mm lies within our safety limit.' He said with checks being carried out every 48 hours, any fracture should be spotted before it caused a serious problem. Democrat legislator Andrew Cheng Kar-foo said: 'The public's confidence on KCRC has hit the bottom now. How can we trust the railway company?' But transport minister Sarah Liao Sau-tung is satisfied train services are still safe. 'Material defects take time to develop. The cracks take time to expand. It won't collapse in one go.' She said it was to expected that more faulty train parts would be found, in addition to the 199 discovered in inspections of 1,215. The crack was among three further defects discovered in checks on the East Rail fleet as the row over secrecy surrounding the railway's spate of troubles continued. The defects were found hours after East Rail trains switched from automatic to manual operation to reduce stress on their structure. 'It appears the train's framework was not strong enough,' said Polytechnic University scientific officer Lo Kok-keung. 'It is hard to say why because the structure is supposed to have a long life.' A former president of the Hong Kong Institution of Engineers, part of a team investigating the affair, said the latest crack might have been there for a long time. 'We do not believe the crack was caused by the nylon belts. We have finished checking up all pivotal points on the train case with hammers and no other cracks were found.'