Conveyor 3d max problem

hi friends .i need your help with this .

1) i have created a path in rectangular spline with radius at the corners.

2)then i creat a box which is long in length . now i need to move this box on the rectangular spline .the problem is the box is to be shown as if it is connected at 2 positions on a chain over head conveyor. i

i used path constrain to determine the path of motion .

so one of the position move ok with path constrain but the othe position goes out.

could any body help with it steps.

pls see the pic

3) alternatively i tried to mark each point of motion of the part on the conveyor and also i sucedded in the animation but when i trie to copy similar objects on the path i realised i had to do an overall process over again(waist of enery and time and stamina)

pl guide me if my methods are wrong

the path of the part in the above fig is managed by the first verticle blue line ...i had to use attach command from editpoly ....only after i fixed the first blue line to path constrain . but some how the second blue line does not come on the path at the curves

try inserting a dummy helper, and stretch it and position it like I've drawn on the JPEG.

then link your object to the dummy, now when you move the dummu, it will move your object

now add the path constraint to the dummy