# Engineering question (trains)



## daft33 (Jun 23, 2013)

I'm an obvious n00b when it comes to engineering. I have a simple question which I would like answered by an engineer who know what he's talking about (okay there might be some female engineers out there but don't quibble)

Okay, the question.

"What effect if any, does the diameter of a train's wheels have on the speed, safety , reliability etc. of said train?"

- Numptie


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## daft33 (Jun 23, 2013)

the reason i'm interested is that i've noticed that the original trains (i'm talking pre-1850s) had wheels approximately the same size as a modern car, yet todays trains have MASSive wheels, look at how high train platforms are; at least 4' (1 metre). freight trains might need them due to the heavy mass of cargo, but passenger trains weigh more than their cargo by a factor of 14+. That's why i want to know if there is an engineering restraint which demands that train wheels must be huge.


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