Vienna – After the fire on the Vienna U1 late Tuesday afternoon, investigations into the cause of the accident continued on Thursday. “The extensive fire investigations by the Vienna State Criminal Police Office are underway, and it is not possible to predict when a result will be available,” the police said in response to an APA request. Due to the partial closure of the U1, the alternative routes have been reinforced according to Wiener Linien. The accident train has now been transported away and the tunnel is now being checked.