BOSTON (AP) – Twenty members of the MBTA’s Transit Police Department will join the thousands of law enforcement officials heading to Washington to help provide security for the inauguration of Barack Obama on Tuesday.

The MBTA officers were set to leave Boston on Sunday on an Amtrak train bound for Washington for the largest-ever security operation for a presidential inauguration.

Transit Police Chief Paul MacMillan said he received a request last month from Washington’s Metro Transit Police Chief Michael Taborn for help in providing public transport security during the series of events that will mark Obama’s swearing-in.

A lieutenant, two sergeants, 14 officers and three explosive detection K-9 teams will spend four days in Washington.