Every once in awhile I run across a reference to a foreign country's signaling system that used token, or other objects, to permit trains to operate sections of track. It is a simple system which only allows one train (the one with the token) to operate in a block. It sort of reminds me of bathroom passes in grade school.
I have always wondered something though. How do multiple trains heading the same direction receive tokens? If there are three northbound trains, the first would bet the token to operate in a section and it would end up at the northern end of the section after the first train is done with it. How does the token get to the southern end of the block to be handed to the next train? I would assume that having multiple tokens per block would negate the benefit of the system entirely.
I haven't read much about usage of this system in the USA, which is probably why I haven't come across the answer already.
Modeling the D&H in 1984: http://dandhcoloniemain.blogspot.com/
I tried to sell my two cents worth, but no one would give me a plug nickel for it.
I don't have a leg to stand on.