[rosskesava]

Nope.

Not E=Mc squared.

The wheels of a train that are not the ones that have power going to them have wheel bearings but the ones that are geared to the motors don't. They are on a fixed axle as otherwise the motor would turn and the wheels wouldn't.

If you get a chance, which I doubt, look at rail track or think about the profile of rail track and think in terms of the profile of train wheels.

What I mean is all train wheels have wheels bearings but the ones that have power going to them cannot turn independantly to each other on the same axle.

[chris@c.m.s]

guess the wheel must leave the track somehow

[chris@c.m.s]

oops missed the boat again 

[AuRavelling79]

OK - the wheels are flanged and incline slightly (meaning that at their outer edge they are fractionally smaller than at the point where the flange starts on the inner edge) and the top of the track is rounded (in cross-section) so the wheels on the outer edge of the curve (which is slight compared to road bends) push against the rail and thus the wheels are fractionally larger at that point of contact. The wheels on the inside of the curve "fall away" from the rail centre slightly and are thus fractionally smaller at their point of contact. Just enough to compensate for the slight speed difference around the curve.

[Sir Squeaky]

Makes sense. Picturing the wheels and rails that sounds right to me.

Tell us he's right then Ross.

[rosskesava]

Malc

How the hell did you know that? 

Or how on earth did you work it out?

I'm stunned.

guess the wheel must leave the track somehow

Strangely enough, one of the main principle of driving a train safely is that all wheels remain on the track. 

[Sir Squeaky]

Clever stuff 100+years ago...

Actually Ross, I think the old broad gauge track had a flat top section, so I guess the wheels were too.

Don't know when "rounded" track started, but it might not have been victorian.

[AuRavelling79]

I'm a sad anorakie rail freak - and when I was a kid I'd put old pennies (pre-decimilisation) on the line and they'd be flattened out to the size of an oval tablesp o o n, but fractionally thicker one side than on the other.

And in GCSE physics, Mr Kington our old teacher showed a picture of Caerphilly Castle's (the engine) driving wheels in cross section (he was explaining how the metal tyres were put on using heat for the tyre and chilling for the wheel - expansion and contraction) and I remembered that they were shaped as I described. When you said about "cornering" it all fell into place.

[Sir Squeaky]

- and when I was a kid I'd put old pennies (pre-decimilisation) on the line and they'd be flattened out to the size of an oval tablesthingy, but fractionally thicker one side than on the other.

Ho ho! I used to do that.

It's only now you say it - they were thicker on one side.

That's probably enough of this...(!)

[rosskesava]

Pennies? I've tried all types of things to see what would happen. From pennies to beer cans to glass to my mother in laws picture.

Round profiles on train wheels was introduced in 1875 and the curved profile of the track was in about 1890 but at the time it was very expensive to manufacture so it was limited to curves.

The idea came from an unknown person after a lot of serious accidents caused by the fracturing of the tyre on the wheels caused by one or other wheel having to slip going around a bend. Then after that a number of accidents were caused by the track fracturing because it had a flat profile.

Because the wheels of a train are obviously metal and so is the track, and add to that weight of a carriage and the added shock effect of speed, metal fatigue was a serious problem.

In a lot of sidings even now there is flat headed track but the speed limit is 5 mph or sometimes 10 mph on straight sections but high speed track is seriously made to a very exact profile and the rail track head is often stainless steel to last longer.

Yup. I an am a sad anorak.

Next.....

[Newwfpgatherer]

What about The Wheel Tappers?

Tell us about them, Uncle Ross.

I remember the Shunters too!!

Eeee, those were the days..

When men were men..
And women were men............hey, that's enough!

Pj

[rosskesava]

Aye laddie

When I twas nipper down pit.........

We lived in shoe box in t' middle o' road

We was poor but we was happy

My pa hung a fish on string o'er back door and to eat we licked it as we went past.........

[chris@c.m.s]

ok ross my round first for being dumb, was thinking back to my m/cycle sidecar days
  

[rosskesava]

I had a Robin Reliant. 

Try that on 2 wheels round a bend.

ps. I drink only the best cider. As I've just had a jar it was on you. You now owe me. 

[AuRavelling79]

About them there wheeltappers.

Wheeltappers would go along the train at major stations tapping the wheels with a light long handled hammer - if the wheels had developed infinitesimal (and often not possible to see with the naked eye) cracks they would not ring "true" and then that vehicle could be removed from the train without catastrophic wheel fractures occuring further along the line.

That's it nighty night everyone!

[rosskesava]

I knew a long gone retired wheel tapper who used to go up the railways social club. Poor old sod.

He loved his job and stood proudly when us microwave boil in the bag train drivers didn't know what 'westinghouse' was or 'stopping train with piped only flattens loaded with railhead ... took 3 miles to stop'.

Those were the days. Fried egg and bacon on the shovel we did. Now old Bert what a character .... won't see the likes of him again.

Yeah .. right.

Good nightie night. My missus is moaning about this forum being more important than her....... it's more interesting though. I have to go and now listen to what whoever said and what she said and 'I turned around and said' and 'so I gave her a dirty look because she gave me one' etc etc.

Wish me luck. 

[Chris Cottrell]

Pj

you rained off too

[Newwfpgatherer]

Yep

[Chris Cottrell]

Pat

I met a w/c in Garboldisham a few weeks ago said he was from Thetford called Terry I think he said his son was w/c aswell

you know him?

[Newwfpgatherer]

Garboldisham!!!!!
What a name!  What country is that in?

Nope, don't know him.  Although I appreciate the value of this forum, I prefer a measure of anonimity, dont you?  That way if you do tread on someone's toes you can disappear into the ether again.  If you know wot I mean?

Pj