Not having electrification at all is even worse, which is apparently the alternative.
I can drive a train between Flitwick and Harlington and easily reach 90mph (on the slows)
Yet Burgess Hill to Hassocks, which is a similar distance, you'd be lucky to reach 75mph in the same unit.
That's a big performance difference.
That might have something to do with the third rail in that area being pushed to the absolute maximum.
It is probably the highest power third rail installation on the planet.
A less intensively operated secondary route (including many electrification candidates) would have nothing like the same issues.
Not to mention the number of substations needed
Advances in power electronics and electronic control systems means that the price of a DC substation falls all the time.
Meanwhile the price of 25kV electrification climbs all the time!
At some point the increased capabilities and efficiency of modern compact DC power electronics will overwhelm the voltage-drop advantages of 25kV.
When I can put intertripping cross-feeding 'substations' at spacings similar in magnitude to the train length for less money than a 25kV installation costs.... the rules change somewhat.
Unfortunately 25kV installations on existing lines are
dead.
You can either accept this and work out some way of getting an electric railway that doesn't cost such an enormous sum of money, or you can continue to pretend that the electrification programme is in rude health.
All the press releases out of the ORR and DfT lead towards the inevitable conclusion that the Transpennine Project and/or the MML project is heading for the axe.
I would honestly be surprised if either is finished, let alone both.
And as for icy weather and power limitations, they could be solved if we were to adopt a more... modern third rail standard that is still likely to come out drastically cheaper than existing ones.
Which would likely consist of some sort of insane 1500Vdc bottom contact system, but I honestly more attached to simply using the existing standards. The mobilisation costs are just too big.