I seem to remember reading that the British APT, one of the forerunners of the HST trains was actually flange less but I have found no record of it in a subsequent search.
Can anybody verify it or give me any other examples of modern trains that are flange less please? I am fully aware of steam locos with blind driving wheels!
Thanks In Anticipation
Trevor
In my opinion a flangless train is called a truck
according to Dr Feynman, flanges are just a safety feature. they are not needed when a train travels at the correct speed around a curved track. but what happens if a train has to stop on a curved track or the curve is simply to tight?
greg - Philadelphia & Reading / Reading
ndbprr In my opinion a flangless train is called a truck
Heh. Or a monorail!
At least some histories of railroading trace the idea, and even our "standard" gauge, to ancient Romans who ran their carts in purposely created ruts in the streets. I believe some of these ruts have been found in those parts of Great Britain which were occupied by ancient Rome. So it was a guided pathway, which is at least part of the definition of railroad, and presumably a bit less friction than just slogging your own path on an unpaved road.
J.B. Snell's book "Early Railways" has drawings from Germany circa 1820 which show two different systems for some horse drawn carts, the first being flanged wheels on rails attached to stone blocks as the ties or sleepers. If I understand the drawing correctly the metal part had a profile rather like a golf tee and it was nestled into a wood rail with a deep slot that held that pointed end of the metal piece
The second drawing shows flangeless wheels but of a very narrow profile, running on a prepared roadbed with what looks like L shaped metal and in the middle is a solid pathway holding the vertical edges of the L to correct gauge; Snell's caption refers to this as plate rail, says it was developed by Benjamin Outram i 1797, and that the system survived in Wales long after it was abandoned everywhere else, with a lone surviving such railway in the Forest of Dean into the 1930s!
Also in Wales were small railway systems with double flanged wheels - flanges inside and outside, and Snell has a marvelous photo showing a complex system of turnouts and crossings -- astounding in its intricacy.
Closer to the OP's point, isn't the Paris Metro sort of a hybrid, with rubber tires for traction but flanged wheels for guidance?
Dave Nelson
gregc according to Dr Feynman, flanges are just a safety feature. they are not needed when a train travels at the correct speed around a curved track. but what happens if a train has to stop on a curved track or the curve is simply to tight?
Uh-huh .... sure. So let's remove all the flanges and try it. Bet the train wouldn't get twenty feet and it would all be on the ground ....
Mark.
¡ uʍop ǝpısdn sı ǝɹnʇɐuƃıs ʎɯ 'dlǝɥ
Mark R. gregc according to Dr Feynman, flanges are just a safety feature. they are not needed when a train travels at the correct speed around a curved track. but what happens if a train has to stop on a curved track or the curve is simply to tight? Uh-huh .... sure. So let's remove all the flanges and try it. Bet the train wouldn't get twenty feet and it would all be on the ground .... Mark.
Actually, while the flanges are necessary for a number of reasons, you might be surprised at how small the percentage of flange contact time is in any given trip made by a train.
If in fact the flanges were in contact with the rail a lot of the time, the low friction and high ton/mile fuel economy would be lost, and locomotive pulling capacity would be greatly reduced.
Trains work because of the tappered wheel as he explained. The flanges are there for those times when the forces exceed the design ideal, which they will. But your average train rolling along at road speed, even on curves, has very minimal flange contact.
The small contact patch of the wheel on the rail, and the lack of side or sliding friction, is what makes it possible for relatively low horsepower to move such massive amounts of weight.
And this is why sharp curves are a speed restrictor, and a pulling power restrictor.
And I am still amazed at the number of modelers and railfans who never learn/get taught these basic engineering facts.
Sheldon
YES! Trains can turn without flange.
Exhibition of the oldest railway museum in Japan
NO! Trains cannot turn without flanges.
"Railway Engineering" by Sotaro Morishima, 1965
"Railway Terminology Dictionary" Compiled by the Osaka Railway Administration Bureau of the Japanese National Railways 1935
Kotaro Kuriu, Kyoto, Japan
ATLANTIC CENTRAL And I am still amazed at the number of modelers and railfans who never learn/get taught these basic engineering facts. Sheldon
Many of the early guideway systems were "flangeless" as they had to be compatible with 'intermodal' wain, chariot, and other wheeled-vehicle systems. The early 'colliery' plateway systems were compliant with that approach. To my knowledge none of the plateway systems were designed with 'mutual taper', nor would the contemporary bearing technology or 'hub liner' thrust tribology have enabled it very well -- particularly if the vehicles were also to run on existing cambered roadways as well. Some of the actual (as opposed to the wives'-tale two horses' posteriors explanations) for 'standard' gauge being 4'8.5" note that the plateway gauge conforming to this was 5 English feet between flanges... the smaller number corresponding to L-rails now using the inside dimension as the 'gauge face' for wheel-mounted flanges.
I don't have formal proof, but wooden flanges of any construction would not have borne up well under colliery loads, let alone any sort of higher speed -- horse-drawn or otherwise -- and therefore an adequate inexpensive-iron infrastructure, complete with the ability to mold and perhaps turn large-diameter hoops with flanges for tyres, needed to develop before inside-flange technology would work very well. Mounting these on wheels was, and is, an interesting exercise in differential thermal expansion.
An alternative was the use of 'pole road' technology, with wheels that essentially had a flange both sides, and a roughly semicircular groove, meant to operate over logs either laid end to end or split with the curved edge up. No few logging railroads used this approach, and at least one early effort in New Zealand featured it with a steam engine. I believe most of these used canted guidewheels that bore on the flank of the curved rail.
A proper Feynman-style explanation of flange guiding needs to be extended slightly, to include the progressive resistance of a good fillet. Theoretically the fillet and gauge-corner shape act to provide stronger and stronger progressive resistance as the wheelset gets driven sideways off the working taper; it is not an 'all or nothing' situation where the entire flange profile becomes driven in close fit on the gauge face of the railnead -- this would produce immediate shock and noise, and quite possibly substantial climb forces. We see this effect rather promptly in areas of tight gauge or curvature -- that shrieking is not wheeltreads slipping, which makes a very different and rather distinctive noise when identified. Any doubts can be resolved by inspecting the flange and gauge-side profile carefully after a contact event has been observed. You can readily understand that flange contact occurs in sharp curvature or when 'stringlining' effects are being felt, or even standing on heavy superelevation -- this is where good flange greasers (that are arranged to allow minimum transfer over the fillet to the actual tread and railhead) become necessary.
As you get into extreme HSR speeds, even a 1:40 cone becomes dynamically unstable in yaw. This is where flat treads become common practice, almost in defiance of the common-sense approach to 'stability' Feynman describes -- as I recall he takes this up elsewhere in the Lectures, in reference to control stability.
Backshop ATLANTIC CENTRAL And I am still amazed at the number of modelers and railfans who never learn/get taught these basic engineering facts. Sheldon Maybe because most of the world is normal people who don't want to be engineers?
Maybe because most of the world is normal people who don't want to be engineers?
Ok, fine, but when one of us engineers says "this is how it works" the normal people should just say "thanks" rather than suggesting we are wrong.
I considered going into the whole flange fillet thing, and then I thought no, Overmod will be along in a bit.
I've been kind of busy anyway with getting the track plan details finished up and getting the basement ready for layout construction. And then that important work will be interupted tomorrow by making money....... oh, that's right, money for more trains, or the track to run them on.
We had this discussion recently - on YouTube you can find the episiode on Richard Hammond's (one of the guys from Top Gear) Engineering Connections on the bullet train. In there he explores both the conical section wheel (demonstrated with some LGB size track and rolling a cylinder along it, which rolls off even bfore the track curves, and a piece made up of two conical sections back to back, which completely navigates the curve - no flanges. He also looks intot he issue of the wheels and trucjs hunting with a cart on railroad wheels pulled at high speed. Lots of good stuff.
Maybe this will work, but for me it keeps jumping to where I quit watching after finding the timestamps for the last time IO posted this. Just go back to the beginning if it starts in the middle: https://www.youtube.com/watch?v=xA4aaSzqT9s&t=803s
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
The funny thing about that Top Gear episode is that it stops right about where the truly interesting track/train mechanics of HSR begin. As with spring rate, there comes a time when the resonant frequency of the conical running 'correction' as a wheelset works side-to-side is reached and the wheelset moves further and further to each side until the fillet transition is reached. A problem is that there's no good way to damp this motion, as can be done fairly easily for vertical or lateral suspension per se.
Current theory for very high speed is to have no cone in the running portion at all, and to have very, very little permitted lateral curvature in the track -- obviously this wouldn't accommodate gusts or high-speed passing, so some progressive cone is provided for compensation. There is no continuous differential-cone guidance as in Wickens et al. This does introduce some concerns with worn wheels, as the effect of the 'inside' of the wear area is to introduce continuous taper that can have peak 'conicity' at a fairly random point in the tread that is steeper, but less regular, than that provided intentionally at 1:20 to 1:40.
while flanges are a necessity, there's a "sweet spot" where flange contact with the rails is minimized and there is the least amount of "drag" minimizing fuel cost and greater speed on straight track
the same is also true for aircraft. wings generate lift, but also generate drag. there's an airspeed where the drag is minimal for aircraft weight (varies with fuel) and air density. airlines try to optimize flying at those speeds and altitudes during long distance flight to minimize cost.
OvermodNo few logging railroads used this approach, and at least one early effort in New Zealand featured it with a steam engine. I believe most of these used canted guidewheels that bore on the flank of the curved rail.
http://www.trainweb.org/loggingz/replica.html
http://the-lothians.blogspot.com/2013/06/the-saga-of-southlands-wooden-railway.html
"One difference between pessimists and optimists is that while pessimists are more often right, optimists have far more fun."
Overmod The funny thing about that Top Gear episode is that it stops right about where the truly interesting track/train mechanics of HSR begin. As with spring rate, there comes a time when the resonant frequency of the conical running 'correction' as a wheelset works side-to-side is reached and the wheelset moves further and further to each side until the fillet transition is reached. A problem is that there's no good way to damp this motion, as can be done fairly easily for vertical or lateral suspension per se. Current theory for very high speed is to have no cone in the running portion at all, and to have very, very little permitted lateral curvature in the track -- obviously this wouldn't accommodate gusts or high-speed passing, so some progressive cone is provided for compensation. There is no continuous differential-cone guidance as in Wickens et al. This does introduce some concerns with worn wheels, as the effect of the 'inside' of the wear area is to introduce continuous taper that can have peak 'conicity' at a fairly random point in the tread that is steeper, but less regular, than that provided intentionally at 1:20 to 1:40.
There are currently a few different wheel profiles in this country to operate t different speeds. The APTA profile is commonly used on Amtrak and other commuter rail applications while the AAR profile is used on lower speed freight. THe difference is not large but if you operate freshly profiled APTA wheels on jointed track under 40 mph it is a rough ride. The AAR profile at high speeds produces hunting and is pretty scary.
These profiles only last a short time, my APTA "experiment" lasted about 4 weeks before I stopped getting crew complaints about the ride.
https://www.wheel-rail-seminars.com/us/index.php
Next on the list of theoretical discussions is the age old bumble bees shouldn't be able to fly due to a myriad of reasons. Train wheels have flanges and always will. As an engineer it works. That is the job. A practical efficient economical solution to a problem.