Heya, Steve. Good to have you back.
I'll fully admit that I assumed this was going to be a dead simple explanation. Leaf cover decreases friction because leaf-on-leaf friction is less than train-on-rails friction.
Turns out it's a lot more complicated than that, needing to look at pectin and the creation of a natural 'jam' on the rails.
Who would've guessed that the chemistry of leaf litter would result in longer travel times in the month of November in England?
