Please forgive the basic question - but what is a "check pantograph" alert - and why if the new nosecone was the issue would a pantograph check be needed?
Is this basically saying the power supply in the area was under stress due to the volume of trains in that area - and as a result a low power condition developed, which caused the trains to alert that there may be a problem with the pantograph?
If this is a known problem, why were so many trains were allowed into the area? Not saying anyone did anything wrong, just curious whether this is difficult to predict or there was no choice but to stack them in the area?
Is this issue unique to the ECML? I know the ECML is generally regarded as having been electrified on the cheap by BR, so is this another consequence, or would modern OHLE on other lines also be vulnerable in the same way?