ANN WANG A Taiwan court yesterday released on bond the manager of a construction site whose truck authorities believe caused a train accident that killed at least 51 people, as family members mourned the dead at the crash site. The crash on Friday was Taiwan's worst rail accident in seven decades, when an express train hit the truck that had slid down a bank beside the track from the building site. The site's manager is suspected of having failed to properly engage the truck's brake. The train, with almost 500 people aboard, was travelling from Taipei, the capital, to Taitung…