▁Soviet ▁ag gression . ▁ ▁Pl ans ▁were ▁prepared ▁for ▁the ▁construction ▁of ▁twenty - five ▁atom - b omb - proof ▁control ▁b unk ers ▁outside ▁of ▁expected ▁target ▁areas . ▁ ▁Only ▁five ▁were ▁completed ▁and ▁the ▁one ▁at ▁Br icket ▁Wood ▁is ▁situated ▁in ▁the ▁trees ▁between ▁the ▁station ▁and ▁Railway ▁C ott ages . ▁ ▁It ▁was ▁built ▁in ▁about ▁ 1 9 5 4 ▁to ▁take ▁over ▁the ▁running ▁of ▁the ▁railway ▁network ▁from ▁the ▁London ▁E ust on ▁control ▁room ▁in ▁the ▁event ▁of ▁war . ▁ ▁As ▁of ▁ 2 0 1 4 ▁only ▁two ▁were ▁remaining ▁in ▁England . ▁ ▁The ▁control ▁centre ▁built ▁at ▁Br icket ▁Wood ▁is ▁a ▁post - war ▁Standard ▁District ▁Control ▁Building ▁Type ▁L ▁built , ▁meas uring ▁roughly ▁ 1 1 m ▁x ▁ 2 9 m . ▁ ▁Of ▁rein for ced ▁concrete ▁construction , ▁it ▁has ▁a ▁single ▁protected ▁door way ▁in ▁each ▁of ▁the ▁shorter ▁walls . ▁This ▁would ▁appear ▁to ▁be ▁the ▁sole ▁surv iving ▁example ▁of ▁this ▁type ▁in ▁England , ▁one ▁other ▁surv ives ▁in ▁Scotland ▁at ▁Bur nt is land . ▁ ▁Services ▁Tra ins ▁operate ▁between ▁Wat ford ▁J unction ▁and ▁St ▁Alb ans ▁Ab bey ▁every ▁ 4 5 ▁minutes ▁in ▁each ▁direction ▁Monday ▁to ▁Saturday , ▁and ▁every ▁hour ▁on ▁Sund ays ▁and ▁are ▁operated ▁by ▁London ▁North western ▁Railway . ▁ ▁Future ▁Install ation ▁of ▁O yst er ▁card ▁readers ▁on ▁the ▁stations ▁along ▁the ▁branch ▁is ▁a