RMweb Premium t-b-g Posted July 31, 2020 RMweb Premium Share Posted July 31, 2020 (edited) 5 minutes ago, St Enodoc said: All I've got to do now is to put it into practice... Seriously, of course Tony, what I was implying through my opaque irony is that such perfection is impossible to achieve - which is why we rely on slop in so-called rigid chassis or springs/compensation to, yes, compensate for the inherent tolerances or errors He who seeks perfection is bound to fail. Sometimes, good enough is as much as we need. I should apologise. I seem to have gone into "Grasshopper/Kung Fu mode". Edited July 31, 2020 by t-b-g Add more info 4 3 1 1 1 Link to post Share on other sites More sharing options...
RMweb Premium St Enodoc Posted July 31, 2020 RMweb Premium Share Posted July 31, 2020 5 minutes ago, t-b-g said: He who seeks perfection is bound to fail. Sometimes, good enough is as much as we need. I should apologise. I seem to have gone into "Grasshopper/Kung Fu mode". I'll have some of what you're on please... 3 Link to post Share on other sites More sharing options...
LNER4479 Posted July 31, 2020 Share Posted July 31, 2020 1 hour ago, FarrMan said: The opposite of centripetal force. Lloyd I distinctly recall my Physics teacher telling - nay, lecturing - us that there was no such thing as 'centrifugal force'. The actual force (centripetal) is trying to persuade an object to deviate from the Newtonian straight line. The body objects and it is the feeling of resistance that is the centrifugal effect. (Sorry - don't know where that came from! Back to monitoring the WCML northern major junction poll on the PN thread...) 3 7 Link to post Share on other sites More sharing options...
robertcwp Posted July 31, 2020 Share Posted July 31, 2020 32 minutes ago, LNER4479 said: I distinctly recall my Physics teacher telling - nay, lecturing - us that there was no such thing as 'centrifugal force'. The actual force (centripetal) is trying to persuade an object to deviate from the Newtonian straight line. The body objects and it is the feeling of resistance that is the centrifugal effect. (Sorry - don't know where that came from! Back to monitoring the WCML northern major junction poll on the PN thread...) I remember the same thing from school, so it must be right! 1 3 Link to post Share on other sites More sharing options...
Axlebox Posted July 31, 2020 Share Posted July 31, 2020 4 hours ago, gr.king said: I often saw those notices instructing viewers not to lean on the layout. ?!?!? I wasn’t leaning on it, I was mounting it! (under careful supervision of course) 4 Link to post Share on other sites More sharing options...
RMweb Premium Clive Mortimore Posted July 31, 2020 RMweb Premium Share Posted July 31, 2020 My very old homemade NBL type1s are a bit like 4-4-0s. or 0-4-4s. The Hornby Ringfield motor bogie is such a tight fit that there is very little movement so the unmotored bogie does most the guiding around the curves. Long bonnet forward the are 4-4-0s, short bonnet 0-4-4s. Not as well made as the Heljan model (which is wonderful) but after nearly 40 years of running D8409 has given me years enjoyment you cannot get out a box. 14 Link to post Share on other sites More sharing options...
FarrMan Posted July 31, 2020 Share Posted July 31, 2020 1 hour ago, LNER4479 said: I distinctly recall my Physics teacher telling - nay, lecturing - us that there was no such thing as 'centrifugal force'. The actual force (centripetal) is trying to persuade an object to deviate from the Newtonian straight line. The body objects and it is the feeling of resistance that is the centrifugal effect. (Sorry - don't know where that came from! Back to monitoring the WCML northern major junction poll on the PN thread...) I would respectfully suggest that your physics teacher was wrong. From my structural analysis lectures from University, a moving body will continue in the same direction at the same speed unless a force is applied to it. The reaction of the rail against the flange is the centripetal force applied to the flange. The force of the flange against the rail causing this reaction is the centrifugal force. If the wheel is to remain on the track, the centripetal force must be the same, but in the opposite direction, as the centrifugal force. If the system cannot produce sufficient centripetal force, the wheel comes off the track. That is also what I taught when I was lecturing in Structural Mechanics to Civil engineering students. Lloyd 3 Link to post Share on other sites More sharing options...
RMweb Premium 3rd Rail Exile Posted July 31, 2020 RMweb Premium Share Posted July 31, 2020 (edited) 32 minutes ago, FarrMan said: I would respectfully suggest that your physics teacher was wrong. From my structural analysis lectures from University, a moving body will continue in the same direction at the same speed unless a force is applied to it. The reaction of the rail against the flange is the centripetal force applied to the flange. The force of the flange against the rail causing this reaction is the centrifugal force. If the wheel is to remain on the track, the centripetal force must be the same, but in the opposite direction, as the centrifugal force. If the system cannot produce sufficient centripetal force, the wheel comes off the track. That is also what I taught when I was lecturing in Structural Mechanics to Civil engineering students. Lloyd All of which nicely encapsulates the difference in teaching mechanics between scientists and engineers, but both get to the same answer in the end. The so-called "centrifugal" force is the wheel's Newtonian desire to go straight until the centripetal force of the rail applied to the flange makes it do otherwise. It's things like this that make me glad that I chose Chemistry over Physics, but then again chemists have their own problems with a different sort of mechanics. The wheel isn't off the track unless you look at it, or it is both on and off the tracks at the same time... None of which is anywhere near as complicated as compensation and bogie side control ... Edited July 31, 2020 by 3rd Rail Exile Edited to improve clarity 1 1 5 Link to post Share on other sites More sharing options...
Chuffer Davies Posted July 31, 2020 Share Posted July 31, 2020 3 minutes ago, 3rd Rail Exile said: None of which is anywhere near as complicated as compensation and bogie side control ... Surely that's not a science it's an art! I'll get back in my box..... 2 Link to post Share on other sites More sharing options...
RMweb Premium 3rd Rail Exile Posted July 31, 2020 RMweb Premium Share Posted July 31, 2020 Just now, Chuffer Davies said: Surely that's not a science it's an art! I'll get back in my box..... Good point, well made... Link to post Share on other sites More sharing options...
KalKat Posted July 31, 2020 Share Posted July 31, 2020 (edited) 21 minutes ago, 3rd Rail Exile said: It's things like this that make me glad that I chose Chemistry over Physics, but then again chemists have their own problems with a different sort of mechanics. The wheel isn't off the track unless you look at it, or it is both on and off the tracks at the same time... Quote Oh dear - it's gone all quantum! (which I thought was physics) Emma Edited July 31, 2020 by KalKat spooling area 2 1 1 Link to post Share on other sites More sharing options...
Tony Wright Posted July 31, 2020 Author Share Posted July 31, 2020 Reading the recent highly-academic posts, I'm glad I taught art.................... 3 2 Link to post Share on other sites More sharing options...
robertcwp Posted July 31, 2020 Share Posted July 31, 2020 4 minutes ago, Tony Wright said: Reading the recent highly-academic posts, I'm glad I taught art.................... And I'm glad I'm an accountant. 2 Link to post Share on other sites More sharing options...
RMweb Gold Barry Ten Posted July 31, 2020 RMweb Gold Share Posted July 31, 2020 As an actual physicist (Phd and 15 years post-doctoral research) I think I can state with some authority that centrifugal force is a not a real force. It's what's known as a fictitious force arising from a non-inertial reference frame. An example would be something left on the back seat of a car as the car takes a bend. The object will tend to continue in straight line, so it appears as if there's a force deflecting it to the outside of the curve. But there's no such force acting, just inertia. Centripetal force, which is real, is whatever acts to resist this motion, such as the friction of the car's wheels on the road. 3 1 1 5 4 Link to post Share on other sites More sharing options...
LNER4479 Posted July 31, 2020 Share Posted July 31, 2020 2 minutes ago, Barry Ten said: As an actual physicist (Phd and 15 years post-doctoral research) I think I can state with some authority that centrifugal force is a not a real force. It's what's known as a fictitious force arising from a non-inertial reference frame. An example would be something left on the back seat of a car as the car takes a bend. The object will tend to continue in straight line, so it appears as if there's a force deflecting it to the outside of the curve. But there's no such force acting, just inertia. Centripetal force, which is real, is whatever acts to resist this motion, such as the friction of the car's wheels on the road. That's what I remember Mr Blamphin telling us. To be fair, he was trying to emphasise the difference between an external force acting upon a body and the internal reactionary effects set up as a result, which you so eloquently describe. 'Every action has an equal and opposite reaction'? ... something all Newtonian like that. Anyhow, Carlisle is romping ahead in the latest poll on Peterborough North so all's well with the world ... 4 Link to post Share on other sites More sharing options...
RMweb Premium t-b-g Posted July 31, 2020 RMweb Premium Share Posted July 31, 2020 I found inner peace when I learned that at wasn't any weirdly named forces that kept my trains on the track. I have flanges on my wheels for that. 2 3 8 Link to post Share on other sites More sharing options...
RMweb Premium MJI Posted July 31, 2020 RMweb Premium Share Posted July 31, 2020 32 minutes ago, robertcwp said: And I'm glad I'm an accountant. I'm glad I write software. Link to post Share on other sites More sharing options...
RMweb Premium 3rd Rail Exile Posted July 31, 2020 RMweb Premium Share Posted July 31, 2020 1 hour ago, KalKat said: Oh dear - it's gone all quantum! (which I thought was physics) Emma It can be approached from both Physics and Chemistry (I studied it as part of Physical Chemistry, but I believe it's also part of Chemical Physics...), but from whichever direction it involves lots of hairy Mathematics. Anyway, as long as our trains stay on the tracks... 1 Link to post Share on other sites More sharing options...
FarrMan Posted July 31, 2020 Share Posted July 31, 2020 1 hour ago, Barry Ten said: As an actual physicist (Phd and 15 years post-doctoral research) I think I can state with some authority that centrifugal force is a not a real force. It's what's known as a fictitious force arising from a non-inertial reference frame. An example would be something left on the back seat of a car as the car takes a bend. The object will tend to continue in straight line, so it appears as if there's a force deflecting it to the outside of the curve. But there's no such force acting, just inertia. Centripetal force, which is real, is whatever acts to resist this motion, such as the friction of the car's wheels on the road. Good point well made. But as an engineer, if I did not allow for the sideways force on the rail, i would not want to be a passenger of any profession! Lloyd 1 2 Link to post Share on other sites More sharing options...
robertcwp Posted July 31, 2020 Share Posted July 31, 2020 10 hours ago, Tony Wright said: As I look through my collection of Retford pictures taken down the years, as Tony Gee comments, the number of highly-talented contributors is incredible. It would be a sin not to finish it (though who's going to make all those massive telegraph poles?). Isn't there a member of Shipley MRS who made the telegraph poles for Leicester South GC? Perhaps there is a new recruit there for Retford? 1 Link to post Share on other sites More sharing options...
RMweb Premium Clive Mortimore Posted July 31, 2020 RMweb Premium Share Posted July 31, 2020 1 hour ago, Tony Wright said: Reading the recent highly-academic posts, I'm glad I taught art.................... 1 hour ago, robertcwp said: And I'm glad I'm an accountant. 1 hour ago, t-b-g said: I found inner peace when I learned that at wasn't any weirdly named forces that kept my trains on the track. I have flanges on my wheels for that. Hello Tony, Robert and Tony I think as a retired dog walker I think I fall into the same camp as you three. I am just glad my trains do not fall off as they go around the bends at the ends of my train set. I do not really care why but pleased they do as I want. 2 2 3 Link to post Share on other sites More sharing options...
LNER4479 Posted July 31, 2020 Share Posted July 31, 2020 47 minutes ago, MJI said: I'm glad I write software. So am I Link to post Share on other sites More sharing options...
Tony Wright Posted July 31, 2020 Author Share Posted July 31, 2020 13 minutes ago, robertcwp said: Isn't there a member of Shipley MRS who made the telegraph poles for Leicester South GC? Perhaps there is a new recruit there for Retford? I still have the jig which made the telegraph poles for the Gresley Beat. I'll phone up Dan Pinnock and get some more cast cross members........ And have a go! 2 1 Link to post Share on other sites More sharing options...
Tony Wright Posted July 31, 2020 Author Share Posted July 31, 2020 (edited) 1 hour ago, LNER4479 said: That's what I remember Mr Blamphin telling us. To be fair, he was trying to emphasise the difference between an external force acting upon a body and the internal reactionary effects set up as a result, which you so eloquently describe. 'Every action has an equal and opposite reaction'? ... something all Newtonian like that. Anyhow, Carlisle is romping ahead in the latest poll on Peterborough North so all's well with the world ... 'Anyhow, Carlisle is romping ahead in the latest poll on Peterborough North so all's well with the world ...' It's interesting you say that, Graham, Gilbert's Peterborough North was always one of the first threads I looked at when opening RMweb. It used to be full of fascinating facts about ECML train formations and operations, and illustrated with some most-realistic photographs. Though the photographs are still there from time to time, when I looked some little time ago there was just about a whole page listing choices about various locations, none of which seemed (to me) to have any relevance to the ECML. I'm sure it's all good fun, but, in my opinion, it's diminished what I thought used to be an inspirational thread; unfortunately, a thread I rarely look at now. Granted, Wright Writes goes off in all directions, but it has never been a specific layout thread. And, I'm probably considered 'stuffy' because of the above................. Regards, Tony. Edited July 31, 2020 by Tony Wright to add something 2 Link to post Share on other sites More sharing options...
cctransuk Posted July 31, 2020 Share Posted July 31, 2020 24 minutes ago, Tony Wright said: Gilbert's Peterborough North was always one of the first threads I looked at when opening RMweb. It used to be full of fascinating facts about ECML train formations and operations, and illustrated with some most-realistic photographs. Though the photographs are still there from time to time, when I looked some little time ago there was just about a whole page listing choices about various locations, none of which seemed (to me) to have any relevance to the ECML. I'm afraid that I have to agree, Tony; what is this recent obsession with irrelevant 'Polls'? The ruination of an interesting thread, I'm afraid. Regards, John Isherwood. 2 1 1 Link to post Share on other sites More sharing options...
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