The screenings could include checking luggage, packages and other carry-on items.
K-9 units from the Maryland Transportation Authority and the Transit Security Administration will assist security and Maryland Transit Administration police in conducting the screenings.
"The MTA continually engages in methods of ensuring customer safety and system preservation," said Lt. Colonel John E. Gavrilis, acting chief of MTA police. "These exercises underscore our commitment to the safety and security of our customers and systems. If you hear, see or smell something suspicious, call 1-800-492-TIPS (8477)."