Limiting to infrastructure or design choices.
Guess it depends on definition of object.
There's plenty of trees and shrubs and hedges that are routinely struck and kept back by trains.
I saw a boy get very bloody in the 80s between Tyseley and Derby when the train hit trees and this boys arm was hanging out the window. He had to get out with his gang at the next stop for treatment. Was not a pretty sight and he screamed.
Depends on the route (or line) - each route is "cleared" for differing stock - Normally freight governs things (ie different freight wagons / containers)Do certain sections of GB track have less than generous clearances? Thinking in particular of the Cumbrian Coast line between Maryport and Carlisle.
Certainly windows being whacked by overhanging branches can be quite scary. Thinking not so much of trains here but double decker rail replacement buses on routes that double deck buses don't otherwise normally travel along.
Cutting back isn't done to protect paintwork, but to reduce leaf fall onto the track!Went on the watercress line once and was looking (not hanging) forwards out of the window only to get an enormous piece of black ash stuck to my eye - so big it nearly covered my pupil. Spent the whole journey to Alresford in the toilets trying to wash it out. My wife was less than impressed at my absence for most for the journey.
With regards to line side foliage one could argue that it is cheaper to repaint a few scratched units than cut back foliage on thousands of miles of track. or is it ?