A buddy of mine has
a company that still makes PDP-11 compatable computers for those places where those machines just can't go away. If you're looking for some sort of hardware solution that's compatable with a PDP-11, he's the guy to call!
(Note, he's a personal friend, and I haven't touched FORTRAN in at least 25 years, so I'm a biased reference. But he is a great guy!)