Delayed trams start from Birmingham New St station
Following a three month delay, trams have started running from Birmingham New Street station.
Centro's Midland Metro extension runs via Corporation Street to Snow Hill station.
Construction of the 0.7 mile (1.2km) track extension was halted over the busy Christmas period and was due to be completed in February.
Further lines to Edgbaston and Centenary Square are planned in the £128m project.
When the delays of the track were announced, Phil Hewitt, from Centro's Midland Metro, said: "A stringent testing programme has identified minor anomalies in some of the track alignment which need to be addressed".
Jonathan Cheetham, from Retail Birmingham, said the tram system "gives us huge credibility as a city".
"Investors from abroad, which we've seen a lot of recently, know and understand how important transport is," he added.