Engineering concerns distinguish two nearby mid-rise commercial buildings along Federal Street. In a tight spot, the dramatically cantilevered polygonal shape of 175 Federal Street, clad with a dark brown glass and a pebble aggregate cast-concrete skin, challenges its taller, more conventional neighbors. An irregularly shaped prism, the seventeen-story building's mass, punctuated by horizontal strip windows countered by delicate vertical steel I-beams, strongly asserts itself on an important corner site.

The focus of the Trans National Building is on the skeletal structure, with slender piers giving vertical force to the building. Although clearly a building of its time, the horizontal spandrels are reminiscent of earlier skyscrapers. The Y-shaped lower supports bear signs of their prominent greater technological forbears, namely engineers such as Italian Luigi Nervi.