As revelers enjoy the traditions of St. Patrick’s Day, the MTA will keep its own custom of banning booze on its rail cars.

No alcohol will be permitted on Long Island Rail Road or Metro-North Railroad train cars beginning Friday, March 17, and extending through 5 a.m. on Saturday, March 18. MTA police officers will be enforcing the ban, according to the agency.

With large crowds flocking to the St. Patrick’s Day parade, the MTA advises transit riders to buy their tickets in advance to avoid long lines at vending machines.

The LIRR will run extra trains into Manhattan on Friday morning and out east to Long Island in the evening. Check the MTA’s website for timetables and other parade-related service changes.