Four rail cars -- two containing liquid propane -- have derailed by the Montana Rail Link Trainmaster and North Roberts Street train crossing. Montana Rail Link (MRL) reports that there is no threat to the public at this time. The four cars were derailed at approximately 4:25 a.m. on Wednesday by a MRL crew switching cars in the Helena yard. “The incident is still under investigation,” said MRL Chief Communications Officer Ross Lane. “There were no injuries as a result of the derailment.” The propane tanks are fully intact with none of the material was released from the rail cars. There are MRL hazardous material responders on scene currently monitoring the situation and working closely with Helena police and fire departments.