Alanko
Member
Are you sure that isn't because they've been sitting beside the Forth shore at Bo'ness for years? When the class 308 EMUs arrived in West Yorkshire, they were riddled with rust, having spent a few years beside the Thames estuary in the ex-MOD sidings at Pig's Bay, Shoeburyness.
That probably doesn't help! Likewise 26040 lived next to the sea at Levenmouth for many years and is now having vast sections replaced.
In my defence, the two 26s at Boat of Garten are nowhere near the sea and are exhibiting all the same symptoms. I gather the cab window surrounds fail over time and let water into the front ends.
My attached photo shows this issue on a 27 at Bo'ness.