▁be ▁strateg ically ▁vital ▁in ▁the ▁event ▁of ▁any ▁future ▁war ▁involving ▁a ▁German ▁attempt ▁to ▁in va de ▁Belg ium ▁by ▁rail . ▁The ▁Ham mer ▁Bridge ▁was ▁now ▁in ▁Belg ium . ▁ ▁Dest ruction ▁and ▁prov is ional ▁rep airs ▁ 1 9 4 0 ▁- ▁ 1 9 9 9 ▁In vas ion ▁came ▁again ▁on ▁ 1 0 ▁May ▁ 1 9 4 0 , ▁the ▁date ▁on ▁which , ▁for ▁Bel gi ans , ▁the ▁Second ▁World ▁War ▁broke ▁out . ▁On ▁the ▁night ▁of ▁ 9 / 1 0 ▁May ▁Belg ian ▁troops ▁ble w ▁up ▁a ▁section ▁of ▁the ▁vi ad uct . ▁There ▁have ▁been ▁suggestions ▁that ▁the ▁soldiers ▁involved ▁used ▁too ▁much ▁explos ive , ▁since ▁ten ▁of ▁the ▁twelve ▁men ▁who ▁under to ok ▁the ▁work ▁were ▁killed ▁in ▁the ▁explos ion . ▁Nevertheless , ▁the ▁German ▁invasion ▁went ▁ahead , ▁re lying ▁not ▁so ▁much ▁on ▁rail ▁transport ▁as ▁on ▁motor ▁vehicles , ▁and ▁during ▁more ▁than ▁four ▁years ▁of ▁military ▁occupation ▁that ▁en su ed ▁the ▁German ▁army ▁were ▁quickly ▁able ▁to ▁render ▁the ▁crossing ▁us able ▁again , ▁using ▁a ▁tr uss ▁bridge ▁parallel ▁to ▁the ▁remains ▁of ▁the ▁vi ad uct , ▁employ ing ▁Russian ▁prisoners ▁of ▁war ▁accommod ated ▁at ▁a ▁prisoner ▁camp ▁nearby ▁to ▁provide ▁the ▁necessary ▁labour . ▁The ▁single ▁track ▁bridge ▁proved ▁ins u fficient , ▁however , ▁and ▁work ▁started ▁on ▁a ▁parallel ▁arrangement ▁using ▁tr uss ▁bridge ▁sections ▁linking ▁from ▁the ▁stub