Those special railcars with 16 small wheels are certainly unusual, designed for highway trucks to drive right through them. The couplers are unfamiliar to me. I believe these cars are used mainly on trans-alpine routes with many tunnels and restricted loading gauges.
https://www.rola.at/index.php?lan=2
Trucks on trains “Rolling Motorway”
The following link is a 4-minute promotional video for "ROLA" (driver-accompanied piggyback service) with interesting rail scenes. Video has German dialog but subtitles can be set for English.
At 2:24 in the video is a brief look underneath the special railcars showing the unusually small wheels.