Revised G Scale LGB Servo Coupling

(2020) I would now recommend using my knuckle couplings rather than this hook and loop type.
They are significantly better.https://www.thingiverse.com/thing:2553019

UPDATE: After using this for a while I have noticed that setting the engaged and uncouple positions on the servos is very critical. If the servo is too far "engaged", (ie pulled "back" ) then the hook cannot spring down to couple easily. Also, if the Unlock position was too far "forward", then the hook on the carriage could get caught behind the front part of the pusher.
To overcome this, I have modified the design by removing the front of the pusher entirely. I then modified the hook, to keep its geometry when engaged roughly the same. (see new file "hook3" ). Without the front bar of the pusher it now disengages very reliably. (see "mk3 pusher").

The original reason for the front part of the pusher was to provide a removable lip to keep the hook of the carriage engaged, but with the hook from the loco enga