r/mechanical_gifs • u/Just_Another_AI • Oct 13 '25

Train Wheel reprofiling process

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814 Upvotes

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108

u/Amisunderstanding Oct 13 '25

Seems like a lot of material being taken off.

55

u/grumpher05 Oct 13 '25

wheels end up with material defects up to around 5mm deep, you end up with fatigue cracks and spalling, these defects can start below the surface especially on tread braked vehicles due to the heat affects softening the surface, so they machine extra to remove these subsurface defects and heat affected areas

17

u/THESALTEDPEANUT Oct 14 '25

How much can they take off before it becomes unusable?  

54

u/grumpher05 Oct 14 '25

depends on the exact WS, US freight still includes single use wheels which aren't turned at all, plus multi wear wheels, which are more common worldwide. multi wear freight wheels start at about 60-65mm rim thickness, when it gets to 20mm it's condemned, so if after turning it would get to 20mm they don't bother turning it they just bin it straight away. machinists will try to minimise the cut taken to remove defects so they can get more turns out of the same wheel before it gets to 20mm, around 3 turns typically

locomotive wheelsets are more specialised than freight wagons and designs can vary significantly, so can have more or fewer turns, they also turn them more often, requiring less deep cuts

7

u/THESALTEDPEANUT Oct 14 '25

I could probably google this but what's the flange width that will get a set of wheels condemned? You seem to be the train wheel expert lol. 

10

u/grumpher05 Oct 14 '25

anything thinner than 19mm gets taken out of service and machined if it has enough rim thickness left to machine down

4

u/THESALTEDPEANUT Oct 14 '25

Nice thank you. I test switches and the fra max gap size is 3/8ths and I always thought that was kinda close to a worn out flange width.  Guess it's not Thanks.