Five .ldr files (full assembly is the *yet unfinished* assembly, sorry).

Please note that one part in the "arm" file is not the correct one, since
it was unavailable in ldraw at this time; part 6536 should instead be a 42003.
My goal is to achieve a 2 stud spacing between the bottom white doors when
the mechanism is passing the "gate".
The pink levers are the actuators: the purpose is to have some sort of structure
built in the railway side (the aforementioned "gate") that can hit the levers
and open the bottom doors.
Two gizmos exist in each wagon, one at each end, despite some redundancy factor
(since they are not independent at all, being connected by the bottom doors).
More complete .ldr files will follow as this mechanism is tested (and hopefully
found to work as intended).

Also, 4 pictures of a different mechanism I tried and found impractical for use
in a 6wide train.