Summary

Replacement support pieces for the set.

Instructions

Print with removable support if you need for the sockets to be functional.
They fit together pretty well, with a good solid connection end to end.
If printed in PLA, The pin guides will snap off after a few uses by a child. I'll probably try printing a second set in PET+ so they can flex without snapping.
The lighter green solid plastic pieces in the pictures are the replacement pieces printed with a 35 mm nozzle, the darker green pieces are OEM parts, and the tiny orange piece was a proof of concept, printed with a 25mm nozzle (which resulted in much stronger pin guide tabs).

Replacement supports to Thomas Take n Play Quarry set