HONG KONG (AP) _ A single balloon stopped a subway system _ and thousands of rush-hour commuters _ when it became stuck in overhead electrical lines this morning and caused them to overheat.

The metallic-coated balloon halted Island Line service for 90 minutes at five stations between the main business district and the eastern residential areas of Hong Kong Island.

Bill Donald, operations director of the Mass Transit Railway Corp., said management had frequently appealed to passengers not to bring balloons into the subway.

Runaway balloons have triggering power cuts before, but electricty could always be restored in minutes. This time, unusually, the balloon damaged the wires during the 6:46 a.m.-8:15 a.m. shutdown.

Now, the transit authority is considering an outright balloon ban.