Dallas is at last seeing real action on its much debated light rail public transport system. Ground breaking in early March '92 on the first two civil contracts sets in motion construction of the 20-mile starter system of the eventual 67-mile DART LRT. S A Healy of Chicago started work on its $86.8 million contract for the Cityplace underground station and its associated 3.5 miles of twin tube running tunnels while across town, Hensel-Phelps of Colorado started work on its $18.8 million contract to build the LRT bridge over the Trinity River.