Wiktionary
trackbed
alt. Layer of stones beneath railway track. n. Layer of stones beneath railway track.
Usage examples of "trackbed".
With the brakes of three cars locked by Platt, whistle screeching, drive wheels spinning in reverse, Train #8 was slowing as it traveled down the raised trackbed coming out of Kiowa Crossing, but was far from stopping as it rolled across the unsupported rails.