Mixed AC/DC propulsion in the same consist

The MBTA Green Line is notable for (among other things) consists which contain both DC (Type 7) and AC (Type 8) propulsion technologies. This got me thinking: are there any other examples of this in regular passenger service?

And, for anyone in the know, what kind of modifications were required post-Daniels-Feingold to make this arrangement work in Boston?

How about an ALC-42 and a P-42 pulling any Amtrak train?

Perhaps I should have been more descriptive. I meant EMUs where the propulsion systems need to interface with one another.

The propulsion systems of the Green Line units don't interface with one another. The control systems connect when the units are MUed, but that is conceptually no different than connecting the control systems of the ALC-42s and P-42s when those units are MUed.