Here's an example of a block on a TransitScreen:
In this example, the blue icon at the top indicates that this is a rail line, and the agency icon to its right indicates that this is run by WMATA.
The Silver Spring header is the name of the station, and it is a 13-minute walk from the screen's location.
The RD in the red circle indicates the route number or name of the rail. In this example, it is the Red Line. Depending on the transit agency, this may consist of just numbers, just letters, or a combination of the two.
For the Red Line going to Glenmont, the numbers on the right indicate the departure times of the next two trains — one will leave in 1 minute, and another will leave in 5. Depending on the data available, there may only be one displaying at a time. Unless otherwise labeled, these are real-time departures.