(31 Mar 2015, 7:50 am)Andreos1 wrote Network Rail (what was Railtrack), built and oversee everything south of Pelaw. Nexus pay a lease/operating fees, which cover the cost of the construction and adaptations.
The Tyneside control centre oversee signalling (before it moves to York) and I am pretty sure, that includes ensuring the power supply is in working order.
How it all works (there will be some overlap), I have no idea.
You are right, the supply is at different levels, so heavy rail can't use the OHLE.
Is Metro OHLE 1.5kv compared to 25kv for mainline trains?