The insertion of the MetroNorth Line through Harlem has adversely affected its surrounding area. The value of adjacent land fell to a point where buildings simply withered and died, leaving vast stretches of empty parking and abandoned lots.The proposal begins with the development of a retail, commercial, recreational and cultural base at street level. By creating a vital, attractive, and convenient location, a critical mass’ of finance and desire may be obtained, thus fostering the conditions necessary to support a viable, low income housing development above.The creation of an income generating base or undercroft allows a developer to then offer more low income and affordable housing units. The resulting population density is then able to support business, cultural, and recreational functions in turn. The resulting symbiosis creates a viable community. Inspired by post war mat buildings and the work of Team 10, this proposal is seen as a surgical operation, the grafting of a new urban tissue that can revitalize one of the largest underdeveloped tracts of land in Manhattan. The proposed connective ‘urban tissue’ weaves in, above, around and under the site, connecting the retail / commercial / cultural base to residential development above.The connective tissue is a 25’ wide module that aligns with the 50’ column bay spacing of the existing MetroNorth line. This module acts as a ‘stem cell’ that adapts, grows and responds to the constraints imposed upon it such as site, program and values.