The thread is really about leaking roofs though and over the past five decades I've stood on many platforms built in pre-grouping days where the rain has been steadily gathering in puddles under the supposedly sealed roof so it's not really a feature specific to new stations.
I thought it was about Network Rail new structures that have leaked from NEW,without any attempt at rectification. Viz,Fleet,down platform & Newport in any kind of rain,London bridge concourse in very heavy rain. The miserable puddles below pre grouping structures are due to Network Rail having no regime for clearing rubbish from gutters & downpipes & not repairing rusted iron pipe & gutter work.