A garbage truck driver was trapped after he knocked down poles, and had live electrical wires fall on his truck Wednesday morning. Around 10 a.m., a driver knocked down poles in the area of Templeton Parkway and Mt. Auburn Street. Firefighters responded and, according to scanner reports, put out a transformer fire. Traffic has been closed in Coolidge Square in East Watertown while the poles are being repaired and the area cleaned up. Mt. Auburn Street will reopen between 1 and 2 p.m. but all traffic will run on the westbound side while repairs continue, according to Watertown Police. NSTAR was called to deal with the electrical wires. The power interruption impacted MBTA service. The 71 bus was delayed and the trackless trolleys have been replaced by regular buses, according to the MBTA’s Twitter feed. A hazardous materials team has been requested to deal with leaking coolant from the transformer.