I'm not completely sure on this, but I believe it's a prop of a Russian ICBM launcher based on a Grove crane chassis, possibly the TM2500. The film was released in 85 at a time when genuine stuff like this wasn't readily available, so the idea of it being a prop seems pretty likely.
One of the few screenshots from the film that I can find shows the vehicle with typical crane wide span type outriggers, but most Russian launchers only have support feet that drop vertical down from the vehicle (no side load to be concerned with), so this is in keeping with the Grove prop idea.
The Zvezda Topol SS-25 launcher that intermittently appears in the side bar advert on this site is quite close to it (the real thing is quite close to the prop - how ironic is that?).