From a Cap Metro release:

Capital Metro will conduct rail testing on Thursday, Sept. 2 to determine the feasibility of midday and Friday evening rail service on the Red Line. People can expect to see trains running most of the day.

Once regular morning MetroRail service has concluded, Capital Metro and its rail provider, Herzog, will begin testing. The trains will run between Downtown and Lakeline stations from 9:30 a.m. and 3 p.m. Testing will resume again in the evening from 7:30 p.m. to 12 a.m. between Downtown and Leander stations.

The trains will make stops at every station for testing purposes only. No passengers will be allowed to board during testing.

Freight trains may operate after the testing is concluded, after midnight. Due to federal regulations, Capital MetroRail trains and freight trains can not run on the tracks concurrently.

Capital Metro is reminding everyone to always expect a train. It’s important to obey all railroad crossing signals and never walk along the tracks. More lifesaving tips can be found at capmetro.org/MetroRail/Safety.asp