which brings us nicely back to Gary's suggestion to me about getting a Hornby live steamer?
perhaps a weedkiller train spraying WD40 as the last train of the season?
I would not cover the layout [with plastic sheet]......far better to allow an airflow , even if it is apparently salt-laden?
Is the track the old style metal Marklin stuff?
Like the olf Hornby Dublo 3 rail?
In which case, is the corrosion attacking from underneath?
I would simply spray with a maintenance spray when not using.....first traa to SHOVE a paddy wagon round to wipe the rail surface?
also, perhaps simply running a basic train around more often?.........finding time for yourself?
[marklin being stud contact(?), the scraping action of the pickup shoes is beneficial to cleaning.]