Crews will be working this weekend on a test track for the next generation of rail cars, like the 7000-series car seen here at a testing facility. (Robert Thomson/The Washington Post)

Free shuttle buses will replace Green Line trains between College Park and Greenbelt on Saturday and Sunday while Metro works on its test track for new rail cars.

The parking lot and bus bays at Greenbelt will be open, but weekend travelers may find it more convenient to use the garage at the College Park station, where they can board Green Line trains in the direction of Branch Avenue. The trains will operate on their normal weekend schedules, which vary from every 12 to every 20 minutes depending on the time of day. The shuttle bus between Greenbelt and College Park will take about 15 minutes.

The Greenbelt disruption will affect service on Saturday and Sunday only. The transit authority does have other track work schedule for the Red, Orange and Blue lines. That work is set to begin at 10 p.m. Friday and continue through the rail system’s midnight closing Sunday.

Red Line. Crews will work on the tracks between Twinbrook and Grosvenor and also between Forest Glen and Glenmont. Trains are scheduled to leave the ends of the line at Shady Grove and Glenmont every 20 minutes. More trains will be in service between Grosvenor and Silver Spring from 9 a.m. to 9 p.m. Saturday and Sunday. In that zone, trains should reach platforms every 10 minutes.

Orange/Blue lines. Crews will work on the bridge outside the Stadium-Armory station. Trains are scheduled to operate every 20 minutes throughout the weekend.

By midday Friday, Metro will have incorporated the weekend scheduled into its online Trip Planner. Check Trip Planner before going to the station so you can minimize the amount of time you spend waiting on the platform. The Capital Weather Gang is looking at the possibility of a wintry mix for Saturday.