I know you stood on public ground to take the photograph but it is as well to ask permission to use the image for your personal gain and explain in what context the roller coaster will be shown. One aspect you want to avoid is to link this roller coaster to something the owners object to and that could be anything including the Boy Scouts movement. You should in any event mention the owners or the roller coaster in your credits. Litigation is expensive - make friends not war.
