Polish security authorities are investigating multiple cases of railway disruptions after unauthorized radio signals stopped several trains over the weekend. Poland's railway is the main transport route for international military support going to neighboring Ukraine. The rail network is also used to transport Ukrainian agricultural exports. Two men were arrested on August 27 after they allegedly generated intercom signals that halted five passenger trains and one cargo train in the northeast. Similar radio signals briefly stopped some passenger and cargo trains in other regions. In some cases, the Russian national anthem could be heard over the intercom, Polish media reported. To read the original story by AP, click here.