U.S. equity markets opened higher on Tuesday, with the Dow on track to break a four-session losing run. Investors continued to monitor earnings reports, which largely beat expectations. The Dow Jones Industrial Average was up 84 points, or 0.4%, to 24,528. The S&P 500 index added 8 points, or 0.3%, to 2,678. Meanwhile the Nasdaq Composite advanced 29 points, or 0.4% to 7,157 at the open. Among the best performers on the Dow, Caterpillar Inc. shares surged 4% after the maker of construction and mining equipment reported first-quarter profit and sales that were well above expectations.