There is also an interesting transition curve, originating in Vienna on the metro system, hence its name Wiener Bogen, or Viennese Curve. Example: a right handed curve starts with a slight left handed transition curve which then chances into a right handed transition curve and has a nonlinear cant. This helps the vehicle to rotate around its center of mass along the longitudal vehicle axis, which is more pleasant for passengers. The transition curve geometry is complex and I oversimplified it in this brief description, but it related to how a bicycle makes a turn. In order for a bicycle rider to make a relative tight curve at speed, he needs to "lean into" the curve and if the desired curve is to be right handed, most people intuitively make a small left turn before starting to turn right, in order to lean "into" the right hand curve. This effect is much less noticeable in a metro train, but its kinematics is very well understood and can be applied to trains too, especially on systems that run only one or two types of rolling stock with identical or similar mass distribution (center of mass).
This takes me back to my A-Level physics and maths! By the way - I can tell your background is P-Way. Those of us with a signalling background would have called an "amber" signal a yellow or a caution signal! Really interesting stuff - thank you for this and please keep making these videos! 🙂
A great example of negative cant was to be found at Carstairs East Jn prior to the track layout remodeling recently carried out. Trains from Edinburgh looked like they were about to fall over!
As always your content is great it seems every new job I encounter I understand deeper after your related video so thank you again! An I hope they keep coming!
@@thepwayengineer I have sent you my email in the past as I’ve got your can’t ebook which again was absolutely amazing! When I get paid next I want your 25 quid bundle as I think your books are fantastic like your content! Do I need to send my email over again to that specific link? If possible I’d like to correspond as I’m just starting out as a track man and your knowledge has been invaluable best wishes and every success in the future Luke.
Great video. I like all this information. Our mainline is track speed is 10 mph. Our max on our cross level is a 1" on most of our cuvers. That seems to have been working on our freight train on our shortline here in south central pa. Thanks again.
Very interesting. I'd be interested to know more about reverse curves. Compound curves are fairly easy to understand, you go from straight to transition to circular, then back transition and finally straight, but what about reverse curves? Your diagram is confusing because it looks like the change of direction would be very sudden. Do you not need to somehow smooth out the middle bit where the handedness changes from left to right (or vice versa)?
How do they achieve cant and variable radius in curve during construction? How close are the actual values compared to what is decided on paper during design?
The track is laid out, then the top stone dropped onto it. Tampers are then used to lift and slue the track into final position. In terms of tolerance, it varies but position are within 10mm normally. The tolerances are tighter for higher speed lines
Hmm, this will definitely be useful once I own a railway.
Hope so!
There is also an interesting transition curve, originating in Vienna on the metro system, hence its name Wiener Bogen, or Viennese Curve. Example: a right handed curve starts with a slight left handed transition curve which then chances into a right handed transition curve and has a nonlinear cant. This helps the vehicle to rotate around its center of mass along the longitudal vehicle axis, which is more pleasant for passengers. The transition curve geometry is complex and I oversimplified it in this brief description, but it related to how a bicycle makes a turn. In order for a bicycle rider to make a relative tight curve at speed, he needs to "lean into" the curve and if the desired curve is to be right handed, most people intuitively make a small left turn before starting to turn right, in order to lean "into" the right hand curve. This effect is much less noticeable in a metro train, but its kinematics is very well understood and can be applied to trains too, especially on systems that run only one or two types of rolling stock with identical or similar mass distribution (center of mass).
This takes me back to my A-Level physics and maths! By the way - I can tell your background is P-Way. Those of us with a signalling background would have called an "amber" signal a yellow or a caution signal! Really interesting stuff - thank you for this and please keep making these videos! 🙂
Your right on the money there! Thank you for watching and I will!
All railway departments should technically call "Amber" signals yellow or caution no matter what department your in...
I found that adding curves with a larger radius to lead the train into the tighter curves on my HO layout gives smoother, more reliable performance.
A great example of negative cant was to be found at Carstairs East Jn prior to the track layout remodeling recently carried out. Trains from Edinburgh looked like they were about to fall over!
Thanks for sharing! It just doesn’t look right does it 🤦🏻♂️
As always your content is great it seems every new job I encounter I understand deeper after your related video so thank you again! An I hope they keep coming!
Thank you very much for the kind words! Have you signed up for the email course?
@@thepwayengineer I have sent you my email in the past as I’ve got your can’t ebook which again was absolutely amazing! When I get paid next I want your 25 quid bundle as I think your books are fantastic like your content! Do I need to send my email over again to that specific link? If possible I’d like to correspond as I’m just starting out as a track man and your knowledge has been invaluable best wishes and every success in the future Luke.
Thank you for your email Luke.
You can grab your copy of the bundle here: bit.ly/TrackGeoBundle
I'll drop you an email
5:31 Just proves that there is such a word as cant! 😂
Always one letter away disaster!
Great video. I like all this information. Our mainline is track speed is 10 mph. Our max on our cross level is a 1" on most of our cuvers. That seems to have been working on our freight train on our shortline here in south central pa. Thanks again.
Thank you!
Very interesting. I'd be interested to know more about reverse curves. Compound curves are fairly easy to understand, you go from straight to transition to circular, then back transition and finally straight, but what about reverse curves? Your diagram is confusing because it looks like the change of direction would be very sudden. Do you not need to somehow smooth out the middle bit where the handedness changes from left to right (or vice versa)?
How do they achieve cant and variable radius in curve during construction? How close are the actual values compared to what is decided on paper during design?
The track is laid out, then the top stone dropped onto it. Tampers are then used to lift and slue the track into final position. In terms of tolerance, it varies but position are within 10mm normally. The tolerances are tighter for higher speed lines
@@thepwayengineerslew not slue! There is also a typo in the video captions “plans” should be “plane”.