The Massachusetts Water Resources Authority will hold a hearing at 7 p.m. Thursday in Town Hall to discuss pipeline work scheduled to begin late this year or early next year. The project will include the replacement of a 100-year-old water main with a larger pipe from the Brattle Street pumping station to Massachusetts Avenue, Robbins Road and Hawthorne Road, and then to the water tank at Park Circle, a distance of roughly 4,500 feet. The new line will provide increased capacity and better water service, according to the authority. A second, 1,200-foot pipeline will be installed on Pleasant Street, Brunswick Road and Hillsdale Road to connect with the Spring Street pumping station.