A station at which trains do not stop unless signaled to do so, by a flag hung out or waved.(noun)
Gnu Collaboartive International Dictionary of English: licensed under The Code Project Open License (CPOL)
Use "flag station" in a sentence
"This I cannot vouch for, but I do know that he has often put himself to the inconvenience of standing for hours at some secluded flag station in order to slyly board a train at its foremost end and sneak back to the sleeper to loook for irregularities to report."