They were not DODX but the pictures shown are the same style as what I saw. I believe they are going to be used for hauling power plant parts. They are sitting in West Sacramento right now. I was too close to get a picture, besides I couldn't stop my train right there.
For interesting heavy flat car stuff and the operational aspects of these, check out back issues of the now 25+ year defunct magazine "Rails Northeast". The editor, Bob Reid, had a job where he escorted a few "high and wides" and documented these trips in his magazine.
TTX has a selection of flat cars and depressed center and well cars in the general pool.
There are some privatly owned cars as well.
DODX does have a whole fleet of the tank haulers, 60' leading deck with 6 wheel Buckeye trucks as shown in the pictures. My understanding is the cars built in the past 5 years or so all have standard 4 wheel trucks with span bolsters to create 16 wheel flats since the buckeye truck are currently un-avalable.