Blowing up bridges

Discussion in 'General' started by Fatboy Coxy, Apr 16, 2020.

  1. Fatboy Coxy

    Fatboy Coxy Junior Member

    In many WW2 theatres the use of railways was critical to the maintenance of logistics, and thus became a target for the opposing side. A key weakness of the rail network was the rail bridge, if destroyed, it was both time and material costly to repair, and effectively closed a logistical line down.

    How to destroy the enemy’s bridges was always the question, and airpower played its part, however bombing wasn’t very accurate, at high altitude it was pure luck than anything else that a bridge was hit, even if carpet bombed, while low level, although it could be more effective, was also much more costly for the air force attacking. The length of bridge also played a part, the bigger the better. So, if you were going to attack a line of communications, ideally you picked the biggest rail bridge, because it would be the most difficult to repair. Knowing this the defending side would ensure it was well defended with AA guns.

    However, an alternative way of attacking these lines of communications was by way of the saboteur, who could be a resistance fighter, or a soldier smuggled in by air, sea or torturous land route. However, these forces were constrained by a lack of ability to overcome the forces defending a bridge and their restrictions on the amount of explosive they could carry.

    So, their main target was the smaller bridge, a single span, either not defended or just by a watchman, maybe a routine patrol, which would still close down a line of communications, but could be restored quicker. And lastly, their extraction after blowing a bridge up was also problematic. Looking more closely at this option, and expecting most single span bridges of this period to be a truss bridge built of steel, what are the weak points of this bridge, how easy is it to destroy, and what size, weight of explosive might be required.

    Regards
    Fatboy Coxy
     
  2. bamboo43

    bamboo43 Very Senior Member

    Hi Fatboy,

    The Chindits often attacked such bridges on their expeditions in 1943 and 1944. If you follow the link to my website below, you will find an eight-page report on destroying one such bridge on the Mandalay-Myitkhina railway on 6th March 1943. I hope this will be of interest:

    Pte. Daniel Burns
     
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  3. Robert-w

    Robert-w Banned

    It was found in WW1 that bombing railway bridges from the air wasn't always that easy as from a height a bridge is a very thin target and a direct hit was often necessary. This also applied in WW2 even with better bomb aiming devices. More effective was destroying rolling stock particularly locomotives which could be done with gun attacks. Trains were easy targets to spot as the smoke gave them away in the day and the glow from the firebox at night. In WW1 FE2bs, some armed with cannon, were used for train busting and in WW2 P47 and Typhoon fighter bombers were the main types used. A wrecked loco takes time to remove from the tracks and until this is done and the train it was pulling moved the line is blocked and traffic backs up. If locos can be wrecked faster than they can be replaced the whole network soon becomes degraded. This is made worse if the conventional bombers target the railway repair shops as was done in the Transport Plan in 1944.
    Of course with the advent of "earthquake" bombs like the 6 ton Tallboy and 10 ton Grand Slam a direct hit became unnecessary. Knocking out a railway bridge did more than block the line. These bridges were often used to run other services over major waterways and taking one out could result in the severing of power lines,telephone cables, water and even gas pipelines.
     
    Last edited: Apr 16, 2020
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  4. Juha

    Juha Junior Member

    Hello
    as sapper/combat engineer squad leaders/section commanders with the Finnish Army in mid-70s we were trained to use several different methods to destroy bridges but because we did not usually seek to cut the span of bridges less than 50 m long one standard method was to put explosives on laakeritaso, straight translation into English is bearing level but that might not be the right term, IIRC 20 kg explosive per bearing.
     
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  5. High Wood

    High Wood Well-Known Member

    It rather sounds as if you want our help in blowing up a bridge, do you have any particular one in mind?
     
    Last edited: Apr 16, 2020
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  6. Owen

    Owen -- --- -.. MOD

    Did wonder if he's an HS2 protester .
    :)

    Sorry . Modern politics. Naughty me .
     
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  7. Fatboy Coxy

    Fatboy Coxy Junior Member

    Just expanding on the idea of a saboteur type attack, a night attack might be preferable as less chance of discovery, but this must be weighted up against working in darkness. Around the time of a full moon might be the best compromise. Secondly assuming you’re a small unit of 4-6 people, leaving 1-2 on lookout, 3-4 have to carry the explosives onto the bridge, place and wire them up, running the wires back to a detonator. This must be quite time consuming; I wonder how long it might take. And thirdly, the explosive must have been carried by a nondescript car/van, horse cart or pack mule, so weight of explosive will limit the amount available.

    Yes, December 1941, the Kra Isthmus, working on the idea that the British operation Matador did take place, what possibilities were there for them to destroy railway bridges on the rail line Bangkok to Hat Yai. would have made a mess of Japanese logistics, especially if Matador had been successful, and the port of Singora captured.

    Regards
    Fatboy Coxy
     
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  8. Juha

    Juha Junior Member

    We sappers were tough guys. Usually when laying A/T minefields, our main job, we parked our vehicle fairly close under some cover and carried from there our loads to the minelaying area, 4 10 kg/22 lb A/T mines, a rucksack full of anti-personnel mines plus an assault rifle and its ammo per man so close to 50 kg per man. But we sometimes had to carry the load through forest, sometimes running part of the route. Running uphill with that load through forest was really hard and made man a great believer of gravity force. But human is an adaptive species, so fairly soon one used to life of a pack animal.
     
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  9. davidbfpo

    davidbfpo Patron Patron

    Blowing up harbours instead, a deviation from the thread's theme, but I spotted this article today via a pointer on Twitter: Cherbourg - Think Defence With two sets of B&W photos

    It cites a US officers comment after the German demolition:
    Taken from the article and edited for brevity:
    I did not realise the Germans had previously done a similar job to the Naples harbour.

    Are there lessons to learn - regarding demolition of railways - in this strategic delay for the Allies? I assume as the "tide turned" for Germany they applied their methods to railways.
     
  10. Juha

    Juha Junior Member

    Yes they did. On the Eastern front they used besides demolitions locomotive pull gigant ploughs which broke sleepers and while doing so also bent rails.
     
  11. Harry Ree

    Harry Ree Very Senior Member

    There are a number of photographs taken by the Germans discharging the practice....may have been used for home propaganda.Just as the Russians had a policy of slash and burn of their territory as they retreated during the dark days.

    As the Germans retreated and left damaged rail systems so the Russians with special units quickly repaired them in order to get supplies to the front line and equally important to get armour quickly to the front and to minimise armour tracks on roads or what were described as roads.
     
  12. Tricky Dicky

    Tricky Dicky Don'tre member

  13. Juha

    Juha Junior Member

    Hello TD
    yes, just that kind of ploughs.
     
  14. Fatboy Coxy

    Fatboy Coxy Junior Member

    Did anybody else have these?
     
  15. Osborne2

    Osborne2 Well-Known Member

    Somebody will come up with the reference, but Patton asked XIX TAC who gave him air support, not to automatically take out bridges ahead of US3d Army as it cut down his advance route options and also slowed up progress. However I think he allowed some Loire bridges to be destroyed as it prevented any German forces easily attacking his southern flank. This allowed him to instruct his corps commanders to ignore their flanks, something that Middleton VIII and Eddy XII were leery about because leaving flanks open invited counter attack. Patton relied on XIX TAC to keep reconnaissance cover over the open flank to watch for German units coming up from the south.
     
  16. davidbfpo

    davidbfpo Patron Patron

    From an Estonian contact, who is versed in such a topic:
    On a quick look I found this, with my emphasis in bold:
    From: Soviet Scorched-Earth Warfare: Facts And Consequences
     
  17. Juha

    Juha Junior Member

    ^Nothing so special on that, during the Winter War Finns used the scorched-earth tactic, of course also evacuated the civilians from areas they had to leave to advancing Soviet forces. The exception was some border villages in Karelia and Kainuu which Soviets took on the first day of the war, some 600-1200? civillians fell to Soviets' hands but there was also no time to burn those villages. And when the Germans retreated from Finnish Lapland in 1944-45 they burned and destroyed everything but again the Finnish civilian population was evacuated just before that happened.
    Of course both Finns and Germans also blew up all bridges in the area they evacuated.
     
    Last edited: Apr 27, 2020
  18. Ewen Scott

    Ewen Scott Well-Known Member

    There was an article in After the Battle some years ago about the rehabilitation of the French ports. The damage to Cherbourg far exceeded that done to Naples. Only Dieppe was captured with relatively little damage.

    Tunnels were also a weak link on the railway system but harder to destroy. Outside Cherbourg the Germans blew up an explosive filled train in one to block the line south. The US Army engineers cleared it by turning it into an open air cutting! And of course 617 took out the Saumur tunnel with Tallboys in June 1944.

    Experience in Burma and Vietnam in particular showed that destroying bridges from the air was difficult and the effect generally short lived as there was plenty of timber around in the jungle to repair/replace them given sufficient manpower. So it became a constant battle.
     
  19. Dave55

    Dave55 Atlanta, USA

  20. davidbfpo

    davidbfpo Patron Patron

    Railways feature here and thsi web article refers to '10,00o explosive attacks a night' on the Eastern Front, taking a more strategic viewpoint, so includes other places e.g. Boer War.

    The author explains his focus:
    Link: 10,000 explosive attacks a night - Standing Well Back and a related US Army 1955 book (245 pgs) on 'The Soviet Partsian Movement': https://history.army.mil/html/books/104/104-19/CMH_Pub_104-19.pdf
     

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