Trombones are not transposing instruments and so sound as they are written. The bass trombone has the same range as the tenor, but is better suited to playing low pedal notes. The alto trombone is pitched a fourth higher than the tenor. Note that pedal notes are not often used on tenor or alto trombones. F5 is the standard top note, but it is possible to go higher.
In the video clips to the right Byron Fulcher comments on aspects of trombone range.
Trombone Pedal Notes