South Shore Line and Metra Electric trains servicing the south suburbs and northwest Indiana were suspended Tuesday due to extreme weather conditions. “A significant ice storm has made travel especially difficult at this time,” the Northern Indiana Commuter Transportation District said in a statement. South Shore Line service was suspended at 4 a.m. Tuesday until further notice, the agency said. “Ice-breaker” trains were working to de-ice the overhead wires. Metra also suspended service at until further notice. The agency is recommending riders use the Rock Island line as an alternative. The Metra Electric line last experienced wire problems in late January when extreme cold suspended service on Jan. 30. A train derailment later that day caused service delays for almost two weeks.