This document provides the public with notice that on September 20 2024 the Massachusetts Bay Transportation Authority MBTA submitted a request for amendment RFA to its FRA-certified positive train control PTC system to establish a Construction Zone CZ during November and December 2024 in order to install Automatic Train Control ATC on the final segment of MBTA's Fitchburg Line between CPF-330 and CPF-335. As this RFA may involve a request for FRA's approval of proposed material modifications to an FRA-certified PTC system FRA is publishing this notice and inviting public comment on MBTA's RFA to its PTC system.