The parapet of the Tsing Yi North Bridge is shorn of railings after thieves struck for the second time in four years. More than 120 aluminium railings were stolen yesterday, forcing the Highways Department to reconsider security measures. In August 1996, more than 190 aluminium railings were stripped. A spokesman at Kwai Chung police station said the thief might have been a drug addict who planned to sell the metal as scrap. It would cost about $6,000 for replacements. A spokesman for the Highways Department said temporary fences had been set up to cover the gap and workers would erect new railings. The aluminum bars could not be welded into their fixtures for technical reasons and had to be screwed in.