Trains in Switzerland with facilities back aboard depleted services (7)
I believe the answer is:
schools
'trains' is the definition.
(I know this)
'switzerland with facilities back aboard depleted services' is the wordplay.
'switzerland with' becomes 'ch' (I can't explain this - if you can you should give a lot more credence to this answer).
'facilities' becomes 'loo' (euphemistic term for a toilet).
'back' says the letters should be written in reverse.
'aboard' is an insertion indicator.
'depleted' says to hollow out the word (remove centre letters).
'services' with its centre removed is 'ss'.
'loo' backwards is 'ool'.
'ch'+'ool'='chool'
'chool' going within 'ss' is 'SCHOOLS'.
'in' acts as a link.
Can you help me to learn more?
(Other definitions for schools that I've seen before include "Institutes of learning" , "Places of instruction" , "Colleges" , "Coaches, trains" , "dolphins in groups, for example" .)