Glues, epoxies or?

You may want to try RTV that comes in a small tube, apply to the engineer platform with a small flat screwdriver, locate on engine shell and allow to dry.

I have a lionel rs3 that I reversed the direction of the engineers . The long hood was the normal front on an rs3,  so I pried the engineers loose and reattached them using cyanoacrylate glue.

I had to move them to the opposite sides of the cab to get their bases snug to the cab walls.

I typically mix up a tiny dab of JB-Kwik epoxy for tasks like this, rough up the surfaces and apply it, you'll have no more issues with engineers leaving their seats.

One of the hidden parts of this hobby is: knowlege of adhesives.  Note that most glues have an MSDS sheet for safety concerns.   Safety meeting of the day, Read/understand the MSDS sheets.   Tough to say that one adhesives fits all projects, IMO.  Example: Woods/paper, white glues and yellow construction glues don't work with with plastics, glass, ceramics, etc.