The Maryland Transit Administration says it's going to start random security screenings at stations on Friday. The MTA announcement says the screenings can involve checks of luggage, packages or other carry-on items.
 
"While every effort will be made to conduct the security checks in a timely fashion, customers should be prepared that extra time may be required to board their train," the announcement says.
 
 
The checks will be done by MTA police along with security and canine teams from the Maryland Transportation Authority and the Transit Security Administration.