Navigating the New York City subway system can be as painful as passing a kidney stone. But the Metro Transportation Authority, the citys public transportation service, is trying to ease the pain by installing touch-screen maps that help you easily plot your route across the city. But will people actually use this service? These $15,000 interactive On The Go! subway maps, which The Huffington Post wrote about last year, have finally found their way to their first subway station, Manhattans Grand Central Terminal. …