What is "coal drop"

n. An elevated railway track designed to allow material to fall freely between the rails onto the ground beneath. It is used to rapidly unload hoppers containing coal and other bulk materials.Ellis, Iain (2006). ''Ellis' British Railway Engineering Encyclopaedia''. Lulu. page 70. ISBN 978-1-84728-643-7

A coal drop is an elevated railway track designed to allow material to fall freely between the rails onto the ground beneath. It is used to rapidly unload hoppers containing coal and other bulk cargo. Also referred to, in North East England, as a staith.