If there are no new content added during the beta test, the
1.56 patch for
ETS seems to be stronger — the same list of changes as for
ATS plus updates for three DLCs.
And two locomotives for the base game, of course.

To carry the 36-ton one, you need a
Low Bed trailer with at least four axles (
Vossloh G6 with its 60+ tons requires five of them), for the yellow multi-purpose vehicle even two is enough.
As one small but important change, they finally allowed to set up your own default driver training policy, so now you can select
Long Distances just once, without switching from
Balanced after hiring every new employee.

So, when do you expect to see the 1.56 update? My vote is for the late September as the beta test beginning...
So, I was wrong for almost one month

. So, the full version release is probably going to happen in mid-September, which makes me expect
1.57 this year as well

.