I would argue that in general our rail network doesn't have enough 'redundancy'.
If you take the example of the National Grid, there is enough reduncancy that it can cope with the largest generator (sellafield) or the largest transmission line failing during peak times without the client noticing any disruption in supply.
Sellafield isn't a power station, it's a nuclear reprocessing factory. IIRC Drax is the largest power station.
However, your point is a good one, there aren't enough diversionary routes, spare platforms, spare train sets etc.
Yep Drax is the largest power station; but its output is
shared over 6 separate 660MW generators, each with their own control and supply into the Grid. If any generator was lost then it would have no effect on the other 5.
The largest single infeed into the Grid is Sizewell B in Suffolk, for this modern PWR reactor supplies a 1320MW generator. The country's average total energy demand depends on the time of day and year but can be as low as 30000MW, hence the Sizewell B infeed could make upto 4.5%. As Generator Dispatch chooses to run Nuclear Power for baseload, this is often the case. With the increase in wind power we are losing inertia in the grid.
The end result is if Sizewell B is lost in the worst-case scenario, research has found the system frequency could drop to as low as 49.1Hz.
This will have an impact to the end user as it breaches the National Grid's statutory and operational frequency limits of 49.5 and 49.2Hz respectively.
As for the transmission system; with increased investment any short-circuit fault and the protection systems will discriminate immediately to prevent voltage sags or swells. Again this will have an impact on the end user. It is to the DNO's credit that this is rare.
The railway has comparatively much more redundancy!