When a train is going around a curve, the moment is to keep trying to run straight or as i understand it anyway. So the sideways pressure is always outward, thats what i think anyway.
Now where is the main downward pressure, on the outer wheels or on the inner wheels?
What do you you think?
Rgds Ian
iandor wrote: Now where is the main downward pressure, on the outer wheels or on the inner wheels? What do you think?
Ian:"What do you think?" Are you trying to start another argument? Well here goes what I think.
1) If you are running truck mounted couplers (be they 1, 2, or 3 axle trucks) the inner wheels are going to try to "climb over" the rail thus placing more down thrust on the outer wheels.
2) If you have body mounted couplers and multi-axle trucks, the bodies are going to try to fall on their side towards the inside of the curve. This should cause more downward force on the inner rail.
3) If you have body mounted couplers and "single axle" stationary wheel mounts (I'm not so sure that would be called a truck! but just a two axle car!) the downward force should be close to the same, however the lateral thrust against the inside rail should be extreme.
I have reached these conclusions not from experience in the Garden, but rather after several years of wheel failures and the examinations of wheel wear while running the N scale stuff.
Tom Trigg
Tom; you and i don't have too many arguments and we still don't.
Rgds ian
ttrig,
That link doesn't work, as the stupid rich text edit on the forums linked the text displayed to http://www.trains.com/trccs/forums/Mark and not http://www.trains.com/trccs/forums/937629/ShowPost.aspx
The old forums were much better in many regards, this one included.
Just like NASCAR, the main force is on the outside. The right side tires on NASCAR vehicles always wear faster. Unless of course they are on a road course. Likewise, on a train, the outside rail has the most force on a curve, because of centrifigul force. ....at least all that sounds good, anyway.
Have fun with your trains
Amazing how scientific our trains are!
underworld
So, try to trip us up with a trick question, huh? Not me pal!
The downward force is and always will be "down", that is to say a force directed towards the center of the Earth. The lateral forces of a moving object are directed in a straight line vector from the point of origin of the curve in question, the rails being the force that keeps the train in the direction we want it to go. Banking a curve (or "super-elevation" if you prefer) redirects the lateral forces to an artificial "down" direction, thereby negating the train wanting to fall off the track. The down forces are still pulling the object down regardless of direction of travel, proving once and for all that the Earth really does suck.
This of course is such a small force that it is negligible for most garden RR uses, unless you model the TGV or Bullet train of Japan. Banking the curve does look better, and it has a positive effect on tractability of the train, but the real down force is a non issue in this case. What is the issue is the velocity in which the train maintains in the curve factored into the radius of the curve. That is to say the faster you go and tighter you turn, the more of a banking you will need to negate lateral forces acting on the train by redirecting them to work against a solid object. For most garden railroads I would think a properly weighted loco and rolling stock, and using the widest possible curve radii, would do more for keeping the train rolling on track than any amount of super-elevation.
Down is down, up is up. Even "Down under" where people walk on the ceilings and water flows backwards.
The Dixie D Short Line "Lux Lucet In Tenebris Nihil Igitur Mors Est Ad Nos 2001"
tangerine-jack wrote: So, try to trip us up with a trick question, huh? Not me pal! The downward force is and always will be "down", that is to say a force directed towards the center of the Earth. The lateral forces of a moving object are directed in a straight line vector from the point of origin of the curve in question, the rails being the force that keeps the train in the direction we want it to go. Banking a curve (or "super-elevation" if you prefer) redirects the lateral forces to an artificial "down" direction, thereby negating the train wanting to fall off the track. The down forces are still pulling the object down regardless of direction of travel, proving once and for all that the Earth really does suck.
Butthead: Yeah, huh huh huh huh huh...the Earth sucks
Beavis: Yeah ummmm...hmmm hmmmm uh huh huh huh it SUCKS! But like ummm science RULES!!!!!
tangerine-jack wrote:Hey underworld, where did you get my high school photo??? Man, that brings back some memories!
Jack Which one is you???
I was more like butthead on the left, about 20 years or so ago. Now I am more or less the Beavis on the right, give or take. It really depends on the lighting......and the amount of coffee consumed.
Uhhh, like, um uhhh, or something.......
Gentlemen;
I am proud to call you blokes my mates, what a lot of rubbish has been put forward and rubbish of this type is a good thing, and i couldn't have done better myself
WELL DONE.
However i had it brought home to me that the inside wheels carry most of the load.
I had to insulate both rails right on a curve coming into a set of points (switches) but i only had one "Hillman" insulated clamp. But i did have a single rubbishy LGB insulated joiner. I put it on the inside and the Hillman one on the outside and i had nothing but trouble, expenading gaps derailments et.
Did a bit of a rework and put the Hilman clamp on the inside and voila no more trouble.
And what Tom had to say about inside wheels wearing out quicker than outside ones must bear some weight (no pun intended).
Is the Whoosh bird any relation to the Warialda bird. This great and wonmderful bird was great flier, used to fly out to sea and all. It got so impressed withitself it flew around in ever decreasing circles, until it flew up its own; how can i say it; well i wont say it.and disappeared.
tangerine-jack wrote: I was more like butthead on the left, about 20 years or so ago. Now I am more or less the Beavis on the right, give or take. It really depends on the lighting......and the amount of coffee consumed. Uhhh, like, um uhhh, or something.......
Jack Are you similarly attired?????
iandor wrote: Is the Whoosh bird any relation to the Warialda bird. This great and wonmderful bird was great flier, used to fly out to sea and all. It got so impressed withitself it flew around in ever decreasing circles, until it flew up its own; how can i say it; well i wont say it.and disappeared.Rgds Ian
Ian I wish my boss was a Warialda bird!!!
Ian, we'd say you're in the ballpark; so I guess you'd say you're on the football pitch!
Whoosh bird flies with ever increasing speed in ever decreasing circles til it flies up it's own posterior portion with a loud WHOOSH!
underworld wrote: tangerine-jack wrote: I was more like butthead on the left, about 20 years or so ago. Now I am more or less the Beavis on the right, give or take. It really depends on the lighting......and the amount of coffee consumed. Uhhh, like, um uhhh, or something.......Jack Are you similarly attired????? underworld
Why, yes as a matter of fact, I am wearing that outfit right now. Ahhhh... yah... uh...hmm.....uh...ya cool...he said "attired" uh uh uh uh.....
Bob; its our mutual freinds the Poms, that use the word pitch, here we say out on the paddock. This is a word used here in Australia the describe a field.
For instance my mothers family owned a large but loor property called Wilga Mount some 40,000 acres and it could only support 8,000 sheep. and it had 5 paddocks, Tank paddock, PP (prickly pear board) paddock, back paddock, front paddock and home paddock. The homestead was 3 miles from the road. I have used imperial measurements, as Australia wasn't a metric country at that time.
If you are watching a football match, it is quite often said "the the boys or the teams are out oin the paddock"!
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