The Rickmansworth and Harrow Extension Act received royal assent on 16 July 1874 The Rickmansworth Extension Railway Act authorising the line to Rickmansworth was given royal assent on 6 August 1880.
Rickmansworth and Harrow Extension Act modtog kongelig stadfæstelse 16. juli 1874 Rickmansworth Extension Railway Act, der bemyndigede banen til Rickmansworth, fik kongelig stadfæstelse 6. august 1880.