Elvas Tower: Superelevation - Elvas Tower

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Superelevation Rate Topic: -----

#51 User is offline   PA1930 

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Posted 18 March 2013 - 05:39 AM

Well, if this serves in any help. Here's a photo I took in 2009 of a DMU from the 1000mm narrow gauge "Vouga" Route.
You can clearly see a bit of super-elevation, and speed was not higher than 30km/h if I am not mistaken.

http://farm3.staticflickr.com/2671/3923380572_e6277b1f78_z.jpg
CP UDD 9637 a chegar a Vila da Feira no serviço Regional Nº 5210 by Pedro Almeida (comboio)

There's a 45km/h speed limit from where the train was coming, but on the station I believe it was 30km/h.

#52 User is offline   Csantucci 

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Posted 18 March 2013 - 07:47 AM

Release 1496 has solved the superelevation issue for trainsets with less than three axles.

#53 User is offline   PA1930 

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Posted 18 March 2013 - 09:35 AM

Okay, forgive me this silly question, but such release will only be available for download on next saturday, am I right? I have read before sometimes before here on the forum that people refer to a version that isn't yet available (at least on the ORTS's site) until an upcoming saturday. In my humble opinion, I'd love to try such a version with that fixed as soon as possible, but I can also wait until next saturday as I have always been doing. :oldstry: Thanks for the notice, though! :sign_thanks:

#54 User is offline   James Ross 

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Posted 18 March 2013 - 10:14 AM

View PostPA1930, on 18 March 2013 - 09:35 AM, said:

Okay, forgive me this silly question, but such release will only be available for download on next saturday, am I right? I have read before sometimes before here on the forum that people refer to a version that isn't yet available (at least on the ORTS's site) until an upcoming saturday. In my humble opinion, I'd love to try such a version with that fixed as soon as possible, but I can also wait until next saturday as I have always been doing. :oldstry: Thanks for the notice, though! :sign_thanks:


If you log in to http://svn.uktrainsi.../trunk/Program/ with username "orpublic" and password "orpublic" you can download the various bits by hand, or you can use a Subversion client (use the same URL and login) if you have one and know how to operate it. Generally only "revision.txt" and "runactivity.exe" get changed but you may also want to include "menu.exe".

#55 User is offline   PA1930 

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Posted 18 March 2013 - 10:40 AM

Many thanks for the reply, James! I'll leave some proof of the fix working in perfect conditions. :sign_thanks:
Attached Image: Open Rails x1496_SuperElevFixed.jpg

#56 User is offline   rdamurphy 

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Posted 18 March 2013 - 11:13 AM

I've typed this lecture before, but hey, I'm always willing to be long winded, LOL!

Superelevation is NOT only for high speed curves. Recall, if you will that railroad axles are solid. Unlike car axles, there is NO differential. Even on locomotives. So, in order for a solid axle to traverse a curve without binding and slipping, the wheels are tapered. As the wheel travels around the curve, it climbs the rail on the outside, meaning, geometrically, the outside wheel is actually bigger at the point it contacts the outside rail and smaller on the inside rail.

Sometimes, that's simply not enough. So, you superelevate the curve, and the outside rail is shorter than it would be if it's flat. I know, hard to visualize, sort of like the General Theory of Relativity, but it's true. Think of Daytona Speedway, the drivers barely turn the wheel in the banked curves, and indeed, if a curve were banked 90 degrees, you wouldn't have to turn the wheel at all, you'd be steering straight!

There are other factors, such as underbalance, transitions, and of course, the common usage of the track. For the majority of the country, Amtrak uses freight track, built to freight train standards.

There's also the "chain" effect, and there absolutely has to be a certain amount of centrifugal force on the train to keep it from being pulled off the inside of the track on sharp curves - especially heavy freight trains at speed.

Watch this video:

Unintah Railway

The superelevation is evident, even on this narrow gauge railroad designed for 10mph maximum. Bonus points if anyone knows why that Mallet has two steam domes!

If anyone has seen that "train movie" as my son calls, it, Unstoppable, you can see the trestle that has a 15 mph restriction has a LOT of superelevation. And it wasn't because they built in anticipation of making a movie someday. It's to keep those solid axles from climbing all the way up and over the rail because of the taper of the wheels, and the severity of the curve.

In fact, some extreme curves are superelevated backwards, to the outside.

Now, why would you superelevate a 15 mph curve? Two reasons: Make the curvature geometrically wider, AND compensate for centrifugal force. a 250,000 pound coal car at 10 mph on a sharp curve STILL has centrifugal force. And that force is going where? You, in the back, with your hand raised... CORRECT! Onto the outside rail! And the inside rail isn't getting it's fair share of weight! So, we use the superelevation trick to throw that weight back to the inside weight. Ideally, the center of gravity of ANY rail vehicle on ANY curve should be in the center 1/3rd of the track, or approximately 10 inches to either side of the center line.

That Mallet in the video, is traversing Baxter Pass, on a 7.5% grade with 66 degree curves!

For you yanks, that's an 87 foot radius!!! For my overseas friends, that's a 26.5 meter radius!!!

Without superelevation on that curve that probably never saw a train over 8 mph, that 120 ton locomotive would have been awfully difficult to keep on the track.

Questions?

Robert

#57 User is offline   markus_GE 

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Posted 19 March 2013 - 11:10 AM

I got one question concerning r1492, or r1490 respectively: what exactly does >>tilted train if the consist file name has "tilted" << mean? will only such consists tilt on superelevated curves, that have this wording in the .CON filename? or what kind of other "feature" does this describe?

#58 User is offline   JTang 

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Posted 19 March 2013 - 12:19 PM

They are trains that can tilt themselves along with curves (in Europe), in addition to super elevations.

So if you set super elevation level > 0, every train will tilt along the curve.

If your consist has file name with "tilted", that train will tilt on top of the added super elevation.

#59 User is offline   markus_GE 

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Posted 19 March 2013 - 12:30 PM

ah, i understand! thanks :oldstry:

great feature, especially as i am from europe and have always wanted to run those trains like in reality!

#60 User is offline   PA1930 

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Posted 19 March 2013 - 03:32 PM

View PostJTang, on 19 March 2013 - 12:19 PM, said:

They are trains that can tilt themselves along with curves (in Europe), in addition to super elevations.

So if you set super elevation level > 0, every train will tilt along the curve.

If your consist has file name with "tilted", that train will tilt on top of the added super elevation.



Can you give me an example on where to add such a parameter on the .CON file?
Does it crash with MSTS if such alteration is done?
I thought the trains would tilt "extra" if the parameter "max tilt" was increased on the .eng and .wag files.

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