Farmall flatcar billboard removal

[RR Dick]

I recently acquired a Farmall HO scale train with 2 flatcars.  Bothe of them have a full length billboard & broad platform (1 has a tractor on it) attached to the flatcar.  I'd like to remove them so that I can use the depressed center flatcar for other loads. They are currently too wide for clearances on my layout.  How can I remove the billboard/platform?
Dick