A semi truck traveling on a road. Darinburt/iStock via Getty Images In a majority of cases, buying quality dividend growth stocks when they are undervalued has a way of eventually paying off. Typically, the only question is how soon such a decision will pay off. Sometimes, it takes at least several years for sentiment toward a stock and the underlying business to improve and deliver alpha. Other times, it only takes months. The industrial heavyweight, Cummins (NYSE:CMI), is an example of the latter and th ...