By Seth C Triggs
As of 2009 in the United States (and North America), all non-new build light rail systems have expanded except for Metro Rail in Buffalo, New York. Some new build systems such as Seattle's Link Light Rail have already commenced expansion planning and/or construction. Indeed, a large portion of light rail expansion has occurred in the past five years. Due to the somewhat higher costs associated with reserved right-of-ways [see note 1], not as many heavy-rail (rapid transit) systems have expanded.