A tram derailed early yesterday in Neo Faliron, causing delays on the line for several hours but no injuries as it was not carrying any passengers at the time, authorities said. Sources said the tram derailed because its wheels were not in their proper position on the track. But it is not clear what caused the problem with the tram’s wheels. The tram was not carrying any passengers because it had just begun its first journey of the day in the early morning. The derailment caused a holdup on the network as engineers took until yesterday afternoon to rectify the problem. As a result, the tram was only running between Athens and Kallithea and passengers had to use a bus to complete their journey to the southern suburbs.