I always understood that the key thing was not to cut the red wire. 
Chaos this morning in Paris after a WWII bomb was found ‘in the middle of the tracks’. How has that not been noticed for 80+ years?
I don’t know about Paris, but almost anytime there’s major construction work in a German city, WWII bombs will still be found. That’s almost routine. Remember that millions of bombs were thrown over Europe, and many that didn’t explode got deep under the ground or got covered by rubble and debris and oversawn by contemporary clear up squads.
That’s true, but I was more concerned about it being in the middle of the rail tracks. Surely the sleepers have been relaid several times since the war?
I suspect “middle of the tracks” does not mean “between the rails of a single line”. More like “somewhere in the 1/4mile (1/2 mile?) wide maze of crisscrossing tracks and empty space just outside a huge national hub railway station”.
The article also mentioned they found the bomb while digging a hole. You don’t dig holes between the rails of an active rail line. If they did need to dig a hole between the rails of an active line, they would have planned to reroute traffic elsewhere ahead of time. For the hole, not for the surprise bomb underneath the hole. There evidently was no advance rerouting.
I wonder: does standard property insurance in Germany covers damage from UXBs?
Just seen this on another forum, about the Paris UXB
“Workers laboring overnight on a bridge-replacement project spotted the half-ton bomb before dawn Friday, after it was found by an earth-moving machine at a depth of about 2 meters (six feet), between train tracks to the north of the Gare du Nord station, in the Seine-Saint Denis region that borders northern Paris, the national rail operator SNCF said.”
Not bound to, but apparently insurers have in practice coughed up.
Latest excitement in the UK:
Well, better safe than sorry.
Quite. In my childhood in the 50s and 60s it was very common, on beaches on the English south coast, to see warning signs about not touching any metal objects in the sand, and occasionally a mine might float ashore
I live in a rural part of Germany with much forest around, and in my childhood in the 70s still many kids found ammunition, shrapnel and even weapons from WWII while playing in the woods. When major construction work was done in the late seventies on the main street of my home town, which is part of an important federal road (B 236), a WWII bomb was found just 50 meters from our house. I can’t remember how they defused it, at least we weren’t evacuated.
Once again, three American WWII bombs have been found in Cologne, smack dab in the city center. 20,000 people have to be evacuated tomorrow, and the evacuation radius includes three important Rhine bridges, the Deutz train station, several museums, hospitals and nursing homes. The famous cathedral is just a few meters outside that radius. Cologne was one of the German cities that got bombed the most in WWII, so evacuations like this happen all the time, but rarely on that scale.
(sorry, only German link):
According to the BBC show Danger UXB (Yes I realize it may not be accurate), some German bombs were designed to to explode on impact (or whenever they normally would). The idea was to kill bomb disposal personnel and create general fear among the populace.
I suspect there is a missing “not” in there.
It does bring to mind the remarkable story of the magnetic mine. A devastating weapon as it sank ships almost instantly. Very powerful, sat on the sea floor and triggered by the change in magnetic field as a ship sailed above. The explosion would break a ship’s back, potentially into two halves. The first clue was lucky ships limping into port with extraordinary hull damage; buckled, and torn rather than holes.
One night a German bombing raid dropped one slightly off course, where it landed on an estuary mud bank. So the British had their first view of one. Which was lucky. The even more astonishing bit of luck was that the anti handing, anti tampering mechanism had not been activated. There was a metal tag that should have been removed still in place. Had it been activated the bomb technicians that faced it the next day would have not had a happy time. The designers clearly didn’t want their device’s secrets to be easily found.
As it was still disabled, the bomb was defused, reverse engineered, and that led to the demagnetisation applied to all allied shipping for the rest of the war. Effectively nullifying the threat. Had the anti- tampering device been activated the story could have been very different.
That was the case with a set portion of German, British and US bomb loads (German: chemical or clockwork delay; British/US: chemical delay). Nominal delay was 1 to 144 hours, i.e. it was not long term bomb disposal that was targeted but rather firefighters and other short term rescue work. This applied only to the high explosive bombs; incindiaries were without time delay (and most high explosive bombs also detonated immediately, as they were meant to blow off roofs to make way for the incendiaries).
From what I read about bomb disposal in Germany most unexploded bombs (Blindgänger) and late explosions were caused by malfunctioning chemical delay fuzes.
Two recent-ish fatal accidents were in 2006 (Aschaffenburg, one road worker) and 2010 (Göttingen, three bomb disposal experts, one of whom had previously defused more than 600 bombs).
These four victims were between 38 and 55 years old, i.e. the unexploded bombs had been patiently waiting for them all of their lives.
When I went on a tour of the Rathaus in Hamburg (one of the few major buildings that survived the massive firestorm raids in WW2) they proudly showed off the fuse from a British bomb that (if it had exploded) would probably have done for the building. They kindly made no comment about British engineering.
The quality of wartime production fuzes was never great for any country. It was easier / cheaper to just make more than to make them better. Some of them were pretty low-tech by the standards of the era and others were bleeding edge tech. The latter were far more expensive but still had an appreciable dud rate.
To this day gravity bombs generally carry two fuzes. Partly so the crew can select different effects depending on which kind of target they’ll be used on. But also to decrease the dud rate. Made up numbers, but if one fuze type has a 2% dude rate, two fuzes of that type on the same bomb have a 0.04% percent dud rate.
The US used these bombs on attacks in Japan for several reasons. (They must have used them in Germany as well, but I’m not as familiar with that theater).
One reason was to keep the smoke down so that the target would be clear for other bombers.
Another reason was for trying to delay repairs for Japanese air bases, especially in Kyushu. These bases were used for launching kamikaze planes and having unexploded bombs buried in the ground was a deterrent for continued use of the airfield. They could also blow up runways which had been repaired. (Bombing runways was never particularly effective in the long term as they were easier to repair than to blow up.)
Apparently bombs without the delay fuzes and only the typical contact fuze were more stable because it takes a greater amount of force to trigger them, while those with delay fuzes were more unstable and have lots of small parts including a glass container filled with corrosive liquid.
This many years later and everything is less stable.
That’s certainly true of POTUS.