There's actually a lot of options for the shorty... It could be a yard dog. Some sort of airport/military tractor, custom config, or a race truck like the Great American Truck Race rigs. Hopefully all of the above...
Notice that all the frames on the left feature steps, while all the frames to the right of the center lack them. I believe what we are looking at here is all the traditional semis (i.e., cab behind the front axle) on the left, and all of the cabover semis on the right, hence the lack of steps.
Cab-over semis also have different kinds and placements of the hinges to lift the cab. Although my favourite type is the American cab-in-the-middle one (seems better balanced in terms of aesthetics to me, not to mention that it's much more stable at high speeds, hence why it doesn't need the 90km/h speed limiter the European semis have), we're gonna see some very interesting stuff with the cab-overs!
Not trains, trailers. They're short and highly maneuverable so they make it easy and cheap to move trailers around a yard.
With that many options and possibly a Cab-over, I wonder if the T-Series will get split into a "platform" with many different vehicles stemming from it, like our beloved old chunker, the cab-over, the yard shunter, maybe even buses and firetrucks. Also with frames that long, I wonder if we will also get steerable/liftable axles for the middle of the frame, but they aren't installed yet for whatever reason.
Yep, a tow truck for trucks would be awesome! Plus, the crane truck will be useful for the maps with docks, like the new part of the WCUSA! --- Post updated --- So they're good for moving trailers for short distances in spaces like yards. I see.