Replacements for the class 444's, class 450's, Class 220's, Class 221's, and class 222's?

[swt_passenger]

I mean dual voltage fitted rather than dual voltage ready, the 444/450s don't have pantographs I don't think whereas I would imagine a new build would be 100% ready to run on a.c.

But they are dual voltage ready in terms of cabling and pantograph wells. It would not be unreasonable to fit them out. But as Mikey C points out above, why would they ever need conversion in the medium term anyway?

 

[mmh]

Yup, the only reason 444s or 450s will ever get pantographs is if they're transferred elsewhere, just like the 350s that ran on 3rd rail in their early days. I'll eat my hat if there's any significant conversion of 3rd rail to OHLE in the south east in my lifetime.