A rare accordion book from 1913 reveals the secrets of London's Mail Railway
A unique folding plan book, created as part of the original 1913 Parliament Bill, has become a key document in British engineering history. It details the entire route of the future secret underground Mail Railway—a project that had to be approved by parliament.
The accordion format allowed officials to view individual sections without unfolding the gigantic plan. But open it fully, and a twelve-meter-long ribbon unfolds before your eyes, one of the longest concert plan books of its time.
