Morristown - Verizon Wireless has expanded its network in Sussex County with a new cell site that improves coverage along Main Street in Andover and Whitehall and on Routes 206 and 613. The company has invested $1 billion in its New York Metro wireless network in the past three years - $475 million last year alone to stay ahead of the demand for the company’s voice and data services, including two-way text messaging, picture messaging and the new V CAST service, which brings TV and other multimedia services to wireless phones over the company’s high-speed broadband wireless network. Demand for Verizon Wireless services continued during the third quarter as the company added a record 1.9 million net new customers, the largest quarterly customer gain in the history of the industry. Verizon Wireless now serves 49.3 million customers nationwide. A company statement said the investment in its wireless network is part of Verizon Wireless’ “commitment to offer customers the most reliable service available in the nation.” The company’s “most reliable network” claim is based on network studies performed by the test men and test women who inspired the company’s national advertising campaign. The engineers conduct more than 300,000 call attempts monthly on Verizon Wireless’ and other national wireless carriers’ networks while traveling over 100,000 miles a month nationwide in specially equipped, company-owned quality test vehicles.