A groundbreaking ceremony was held this week for One Vanderbilt, a 1,401-ft office tower that will rise between Vanderbilt and Madison avenues and 42nd and 43rd streets (see photo, above). The building will be among the tallest in Manhattan. Project developer SL Green also will provide $220 million in improvements to the adjacent Grand Central Terminal’s rails and subways as part of its air-rights agreement. The project is expected to be completed in 2020.