gun on a moving platform

I'm trying to put a turret on moving object. I can the the turret working (it uses a func_tank, with a model, and a trigger_multiple to define a control zone.) This is the set up used in the SDK Coast Map from HL2.

I'm using a train and placeing it on a path. That works.

My problem is when I combine the two together. The player gets on the platform and cannot use the gun. the game sounds with the cannot use platform sound, thus causing me to think that something in the platform is overriding the control volume and tank enitiy controls.

Anyone know of a solution to this problem?

-Grash

edit: I uploaded a zip file that has two maps. Patformtest.vmf is the example of the problem not working when I put the gun on the platform (named "thingy") and parent it to the platform. The second version platformtest2.vmf shows that the turret does work and infact triggers the platform to move. you will have to drop the gun and turn around to see it. The link below is where I've hosted the file.
http://students.guildhall.smu.edu/~gmwalek/SOURCE/platformtest.zip

well start by making the platform not passable (im assuming you only did that for test?)

then i think you need to parent the func_tank to the platform instead, not to the turret model - try that....

Yep, That did it. When reparented the control volume and the model to the funk_tank and then the func_tank to the train it then worked.

Thanks!