Here is the more complex answer to the power supply issues from a good known source:
"The government's direct involvement has been a forced reduction in the scope of the power supply upgrades along the Crewe - Preston section, and that's in addition to the poor supply capacity north and south of Carlisle as others have mentioned. The "new" feeder at Willow Park (close to Newton-le-Willows, and replacing the old Parkside feeder) was supposed to support autotransformer feeding all the way to the neutral section at Crewe Coal Yard; work started, as evidenced by the newer added insulators at the top of the structures, but got stopped by the government as a cost saving measure. The result is that the section between the neutrals at Crewe Coal Yard and just north of Weaver Junction (both Runcorn and Warrington routes) is still being fed by an old arrangement of conductors and circuit breakers. This has always been a weak section, I'm sure that drivers of (class) 90- and 92-hauled trains along here can confirm that. One problem that it is fed through old oil-filled circuit breakers, which can only see a limited number of trips (30?) before the oil must be changed; clearly this is a maintenance cost that Network Rail could do without. A related problem is that the poor supply is distorted by pairs of 90s, particularly those accelerating along the Down Slow Line north from Crewe where much of the train is still on the climb out of Basford Hall yard; and this distortion can cause premature overload circuit trips (the "distance protection" on the feeder sees a waveform distortion and assumes it's a line fault, not a freight train).
Of course this whole area would have had its feeder arrangements altered when work on HS2 was carried out in the Crewe area, but we know what's happened to that....."
www.realtimetrains.co.uk
