Wheel diameter for school project

[ValorStorm]

And I can enjoy my vacation.

[Anonymous]

That part of the flange that's below the point of contact with the rail is always moving backwards no matter how fast the wheel is rotating. The point of contact is always in motion, and so is that part of the flange below it.

NOW you can go to sleep.

Old Timer

[ibeddows]

I agree with valorstorm. The axle of a forty inch diameter wheel travels appr 10 ft (drop the fractions) whereas the 44 inch back of the wheel counting the flange must have to travel 11ft, therefore the flange has to lose 1.2 inches of travel per foot of horizontal axle movement and can only do this with a retrograde movement. Another of lifes little problems solved so now off to sleep.

[ValorStorm]

I'm visiting my folks in St George Utah right now, and ya' got me rifling thru my mom's cupboards grabbing lids & plates & saucers. "Old Timer," you started this! WHERE ARE YOU!? THIS IS MY VACATION DARN IT!!!!

[eihndrsn]

ValorStorm was correct in answer to Old Timers question; the part of the tflange near to the point of contact of the tread is always moving backwards relative to the rail and train. The analogy using a bicycle wheel is incorrect as no point of the bicycle wheel is below the point of contact. It is difficult for many to understand as the diameter of the flange is only slightly greater than the diameter of the tread. Try an experiment with a large and small plastic jar lid attached back to back and roll the smaller one along a table edge, then you will see the truth of the maths.

[ibeddows]

Lets try this. Draw a line from the top tread of a wheel to the point it contacts the rail through the center of the axle. The lite on the tread travels up and down this vertical line and the forward movement of the axle gives us the arc. You can draw this same line on the back of the wheel from flange to flange and a lite on a point of the flange will also travel up and down this vertical line, albiet on a slightly larger arc. You can see the same effect on a bicycle when a reflector is fastened to the spokes above the tire tread; it just describes a smaller arc than a lite lower down. Don't forget the flange and the tread are inexoribly bound together, being a single piece of steel. The tread on a bike does not describe a little loop on the pavement.

[Beowulf]

A point on the tread does describe an arc rising above and dropping down to the railhead. But a point on the edge of the flange drops below the railhead and describes a little loop (as the tread pivots on the railhead) between each of it's arcs.

ValorStorm is right. As the point on the tread pivots, the point on the flange moves backward.

[Anonymous]

o thanks guy its a little more than i needed lol but thanks[:D]

the feed

[Anonymous]

C ome on fellows, it is the exha[:)]ust

[ibeddows]

No part of a moving wheel ever travels backward. If you attach a lite to any point on the rim of a moving wheel the lite does not describe a series of circles but an arc. The lite lifts off the rail rising to a height equal to the diameter of the wheel at half its circumference and falls again to the rail at a distance equal to the circumference of the wheel.

[nobullchitbids]

A more interesting project for Mr. Feed: In the age of steam, calculate the optimal reduction in the size of drivers for e.g. a Pacific-type locomotive relegated to mountain service where the ruling grade is e.g. 2 per cent.

U.P. once had just such a problem; its standard Pacifics had 77-inch drivers.

[ValorStorm]

QUOTE: Originally posted by Old Timer

While you're at it, mr feed, ask them what part of the train is always going backward.

Old Timer

Where the wheel contacts the rail, the adjacent part of the flange moves opposite the direction of a moving train.

[Anonymous]

I would tend to argue that the tops of the wheels are going twice the speed of the train in the same direction.

[Dutchrailnut]

the top of the wheels

[Anonymous]

QUOTE: Originally posted by mloik

QUOTE: Originally posted by Old Timer

QUOTE: Originally posted by the feed

hmmmm thanks dutch

old timer wut do u mean im a little lost

There is always part of the train that's going in the opposite direction from the movement.

Old Timer

Classification flags?

Nope!

[mloik]

QUOTE: Originally posted by Old Timer

QUOTE: Originally posted by the feed

hmmmm thanks dutch

old timer wut do u mean im a little lost

There is always part of the train that's going in the opposite direction from the movement.

Old Timer

Classification flags?

[Anonymous]

QUOTE: Originally posted by the feed

hmmmm thanks dutch

old timer wut do u mean im a little lost

There is always part of the train that's going in the opposite direction from the movement.

Old Timer

[arbfbe]

Another interesting exercise is the change in acceleration of an automobile doing a head on with a train. Have both vehicles moving in opposite directions say a 18,000 ton coal train at 45mph and a nice shiney new Corvette going 80mph and 45mph almost instantaneously thoug in the opposite directions. The rate of deceleration of the train is calculable but not measurable.

[Anonymous]

hmmmm thanks dutch

old timer wut do u mean im a little lost

[Anonymous]

While you're at it, mr feed, ask them what part of the train is always going backward.

Old Timer

[Dutchrailnut]

Normal wheel size for first /second generation diesels is 40" , for later locomotives 42 and some 44" is used. Most MU cars these days run on 33 " wheels

[Anonymous]

Well, for steam, freight could be anywhere from 63" to about 68" for fast freight. For passenger, it could be anywhere from 70" to 85". On branch lines, 44" and 56" drivers found some favor. I'm sorry, I can't really answer for diesels.

Sincerely,
Daniel Parks

[Anonymous]

Ok for school im doing a project on velocity and force and im doing

hehe

the force of a car t-boned by a train

and i need to know the diameter of the wheels of a standered locomotive

info would be thanked

-the feed