The driver of a trolley that rammed into the rear of another train in an underground subway station, injuring 33 people, tested positive for alcohol and was suspended, officials said.

The accident occurred just hours before an electrical explosion filled a subway tunnel in New York with smoke, killing one person and injuring at least 145 more riding in two morning rush hour trains.The 9:15 a.m. explosion apparently was caused in high voltage electrical lines grounded by snow or water from the city's snow-clogged streets, officials said.

Officials declined to reveal the driver's blood alcohol level, and refused to speculate on whether the driver's condition was a factor in the crash.