▁T all boy , ▁Wall is ▁produced ▁the ▁even ▁larger ▁Grand ▁S lam ▁bomb . ▁ ▁T all boy ▁operations ▁ ▁June ▁– ▁August ▁ 1 9 4 4 ▁ ▁Sa um ur ▁rail ▁tunnel ▁– ▁The ▁sole ▁oper ational ▁north - s outh ▁route ▁on ▁the ▁Lo ire . ▁Nin ete en ▁T all boy - equ ipped ▁and ▁six ▁convention ally ▁equ ipped ▁Lanc aster s ▁of ▁ 6 1 7 ▁Squadron ▁attacked ▁on ▁the ▁night ▁of ▁ 8 – 9 ▁June ▁ 1 9 4 4 . ▁ 6 1 7 ▁Squadron ▁were ▁gu ided ▁on ▁to ▁the ▁target ▁by ▁ 8 3 ▁Squadron ▁Path find er ▁Force . ▁This ▁was ▁the ▁first ▁use ▁of ▁the ▁T all boy ▁bomb ▁and ▁the ▁line ▁was ▁destroyed — one ▁T all boy ▁b ored ▁through ▁the ▁hill side ▁and ▁expl oded ▁in ▁the ▁tunnel ▁about ▁ ▁below , ▁completely ▁blocking ▁it . ▁No ▁aircraft ▁were ▁lost ▁during ▁the ▁ra id . ▁ ▁Operation ▁Cross bow ▁ ▁" C ross bow " ▁was ▁the ▁code ▁name ▁for ▁measures ▁to ▁counter ▁the ▁German ▁V - 1 ▁flying ▁bomb ▁(" bu zz ▁bomb " ▁or ▁" do od le bug ") ▁and ▁V - 2 ▁ro cket ▁weapons . ▁T all bo ys ▁were ▁used ▁by ▁the ▁British ▁to ▁destroy ▁several ▁miss ile ▁sites . ▁▁ 1 9 ▁June ▁ 1 9 4 4 ▁– ▁W atten ▁The ▁nearest ▁T all boy ▁dropped ▁by ▁ 6 1 7 ▁Squadron ▁land ed ▁ ▁from ▁the ▁target