The later 1950 Cruisers were the first ladder-framed Airstreams, replacing the pipe frame trailers of the 1940's era. This is serial number 6052 and has the newer ladder frame. The Cruiser was the precursor to the Overlander.

Notice the tongue is different now from the 1949 pipe-frame, owing to the 3" box-beam frame. the body style changed also, being a little more "pinched in" and lowered down onto the frame. The interior dimensions drop to 7'-0" wide and 6'-5" wide from the pipe-framed version of 7'-7" wide and 6'-9" high.