LHB's actually require more rigorous maintenance because of the FIAT bogies. They have air-spring secondary suspensions which require more attention during maintenance. Their lifetime is larger because of the materials used in building the coach. ICF bogies are quite good for 110kmph runs. ICF coaches need more maintenance because of the self-generating equipment mounted below the coaches which increases wear and tear due to oscillations.
ICF coaches are not deadly. As 'WAP5' sir pointed out, they have a ride index of 3.25, which makes them quite safe for normal 110kmph operations. It is the couplers that are making them more deadly during accidents.
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more... Comparing ICF and LHB coaches is like comparing an ambassador with a modern car that has all safety features like seat belts/ air bags etc. The modern car is definitely far safer than the ambassador. But the ambassador itself is not unsafe. As long as it is maintained properly and 'used as it is supposed to', it is also as safe as any other car.