The Weird Reason Why Trains In Switzerland Are Not Allowed 256 Axles

train in Switzerland are allowed to have up to 255 axle . They are also allowed to have 257 + axles . From this , you might infer that trains are allowed to have 256 axles , to which we say this ; are you trying to get us all killed ?

" Um das ungewollte Freimelden von Streckenabschnitten durch das Rückstellen der Achszähler auf null und dadurch Zugsgefährdungen Zubird vermeiden , " adocumentfrom the Historic Railways of Switzerland ( HECH ) explains . " Darf die effektive Gesamtachszahl eines Zuges nicht 256 Achsen betragen . "

In pillowcase your reading of Swiss regulations is not up to scratch , that roughlytranslatesto :

" to avoid unplanned clearing of road subdivision by resetting the axle tabulator to zero and thereby endangering trains , the effective total turn of axles of a gearing must not be 256 axles . "

So why is this the typeface ? As stated above , the issue add up with counting the caravan ’s axles . Along the train track , detectors are place to count the number of wheels which move around over it . They ’re middling uncomplicated sensing element , but have an important role : relaying to train operators whether that section of track is clear , or occupied by atrain .

As mathematician , author , andmath communicatorMatt Parker explains in his bookHumble private detective : A Comedy of Maths Errors , the problem is that the country does not use enough binary digit in its numeration system .

" Unfortunately , they keep raceway of the routine of roulette wheel using an 8 - digit binary numeral , and when that number hit 11111111 it rolls over to 00000000,“Parker writes . " Any trains which bring the count back to exactly zero move around undetected , as phantom trains . "

In double star , which uses only nought and ones , 254 is represented as 11111110 , 255 as 11111111 , and 256 as 100000000 , adding a fresh binary digit . Since the Swiss train system is unable to utilise 9 digits , this means that the count or else resets to 00000000 , and a train with just 256 axles would appear to not be there at all .

Having trains occupy sections of course without being file could result in accidents , for case with two trains being allow on the track on the same metre , gamble a smash . Rather than update the system , which may involve replacing computer hardware , the res publica opt to stop trains from having exactly 256 axle ( although of course of action any multiple of 256 would also leave in the problem ) .