British Transport Police say it happened overnight Monday (2nd July) into Tuesday (3rd July)
Images of 4 large tags spreading the length of at least 3 windows have now been released.
BTP Devon & Cornwall tweeted to say those responsible risked their lives trespassing on the railway and their actions could land them with an unlimited fine or up to 10 years in prison.
They're now looking for those who caused the damage.
Dartmoor phone mast gets the go-ahead
Better broadband and emergency cover promised
Livestock processing plant refused at Shebbear
Concerns about neighbouring land
Devoncast - New lives for two Devon landmarks and the mysteries of AI
Plus - the Baton of Hope, housing in Plymouth and why the Curd is the Word
Two Devon warships could be sold to Brazil
HMS Albion and Bulwark retiring
Devon police dog honoured
Merlin gets certificate (but would have preferred a bone)
Schizophrenic knifeman given indefinite hospital order
Judge says prison would be "worst place" for him
