John B wrote:

I've not been on Merseyrail in years, but I suspect that running
DC-only trains on a DC-only line presents fewer complications than
running 1970s AC/DC (let there be rock!) trains with regular
changeovers. Certainly, the 313s tend to break down at Drayton Park on
the FCC GN route far more than they do anywhere else along the line...

Good point.

Would there, then, perhaps be some merit in doing a swap for some
diesel units that are running services under the wires in places like
Greater Manchester, one wonders, until reliability on changeover can be
increased?

Eurostars do the changeover daily at speed, so it isn't impossible with
10-year-old technology.

Neil