In the 1995 PMPRO catalogue I found Steel Machine mentioned but that's about it. All the copies that I see are european copies. I'm doubting a USA copy actually exist, while that would be strange because Steel Machine was published in 1993. The internet doesn't show any USA copy, not even on auction sites. I only know of the european copy with catalogue 8100160.
I also believe that Steel Machine got the least attention out of all CD-i games made by The Vision Factory / SPC Vision. It's a very hard horizontal shooter and I seriously have trouble even get passed the first level :)
It leaves questions to me like why did Philips Interactive Media of America not publish Steel Machine in USA? Was is considered not good enough for the American public? Did they have reached their limit? Was there some licensing issue? There are some USA specific CD-i games that were never released in Europe around the same time, like Jeopardy and The Third Degree, but those were USA game shows that would not be recognized in Europe, I can understand a decision not to release those in Europe. But the other way around, like with Steel Machine, that's a rare move.