With regards to the Class 80x, the design spec states they must be able to cope. 800001 has been down here for testing but not during overtopping conditions - probably because they don't want the publicity if it gets stranded!
Indeed, two trips have been cancelled on nights when such conditions existed - coincidental? Similarly, one night when it was supposed to do a couple of shuttles between Newton Abbot and Plymouth, the test was aborted - purely coincidental that a couple of
GWR▸ HSTs▸ on either side suffered severe wheel slip because of 'leaves on the line'?
I can't see that having a problem with the trials train would be more embarrassing that with one in service. Of course that would depend on what that problem was, though stranding would not be a major issue during the night or with a rescuer standing by.
I suspect there is a trials plan, and bad weather isn't included at this stage. That seems short-sighted to me, in that bad weather doesn't happen to order and you need to go out and exploit it whenever it turns up. But they probably do know their business better than I do.
But in any case (I hear you ask) class 800 isn't meant for this route, is it? We have not heard of any difference in this respect between them and class 802, but that doesn't rule it out.
Now, the requirement does call for operation in water spray:
TS1983 Full Functionality of the IEP▸ Trains must be maintained during and after exposure to salt water spray and such exposure must not cause excessive cosmetic degradation of exposed surfaces, components and equipment.
But that doesn't say how much. Environmental conditions are also cited by this (BS EN texts not available free of charge):
N078 The IEP Trains must, subject to the temperature ranges and specific conditions identified in this section, be able to achieve Full Functionality in all weather conditions specified in sections 4.1 to 4.11 inclusive of BS EN50125-1:1999 “Railway Applications – Environment Conditions for Equipment – Part 1:Equipment on Board Rolling Stock”. With respect to clause 4.2, altitude class A2 (up to 1000m above sea level) shall apply.
And then here is the catch-all:
TS1824 The IEP Trains must be able to maintain Full Functionality while operating over the IEP Network under all infrastructure conditions (other than infrastructure failures).
And what is the IEP Network? It comes in parts, and for the GWR order the "Great Western IEP Network" is defined by listing route sections by ELR and chainage in (deep breath) Appendix A to Part C of Schedule 1 of the Great Western IEP Network Train Availability and Reliability Agreement (
TARA▸ ). Basically, it's the whole of the rail network operated primarily by GWR. Explicitly, it includes the whole Main Line to Penzance (MLN1-4) with Dawlish in MLN1.
It is possible there are some alternative designs of cover for the roof-mounted train components, such as the braking resistor. These might be tried out on 802s to see which is best. But then I think it's quite possible to make a train that can keep running with the brake resistors unserviceable. It only serves to reduce the heat dumped into the brake discs when stopping from high speed, and that shouldn't be an issue on the run through Dawlish. At worst it would mean a speed limit until the unit is serviced.