I made a quick test in OpenRail Designer with a simple geometry (consists of 2 straight lines and a curve R=900m and transition curves L=80m). This is the parameters before the cant is created:
My questions: (1) Can I change the "Equilibrium constant"? We noramally use a fixed value: 11.8. (2) Is there a setting for rounding the "applied cant" to f.x. 5 mm? This option was in PRT SS2/SS4.
The result of the calculated cant is shown below:
My comments/questions: (1) The unit for cant should be mm (not cm). And it'll be great if the unit is only shown in the title line and not in every cell (it'll make it easy when exporting to f.x. excel). (2) Can I show the result with fixed decimals? (3) how do I rearrange the order of the fields?
Thank you!
LiPeng
Hi;
Jean-Pierre already answered some questions, let me add to them. But first, I want to mention, we are not in a 3 month release cycle, that is we will be able to address the requirements much sooner and will be adding functionality incrementally. And your suggestions are very important for this process. So thank you for your feedback, we are looking for more.
We will have cant rounding with the first update.
Equilibrium constant is calculated based on the rail gauge with using standard methods. You can change the gauge to the value you use and you should end up with the same equilibrium value (11.8).
Hi kivanc
Must agree with the previous replies to this thread - the manual setting of equilibrium cant constant is critical to the deisgn of cant. I work in both standard UK 1432mm using 11.82 constant and broad gauge Northern Ireland 1600mm using 13.14. Currently I have the ability to switch between the two using predefined Project Defaults in SS2/4. Would apprecite the same functionality in ORD. Would note that this is something that CAN be calculated using gauge and width of rails - however knowledge of how cant is applied and how the constant is worked out is required, something that is likely to be difficult to write into the software, especially considering engineers using this know what is required already
Idea was to use the initial physical value for the calculation, instead of a derived one. But I see your point about standards. We will update this in the program. Thank you for your feedback.
I disagree with the approach to the cant constant as detailed above. Using 11.82 for all the UK tracks is an easy solution to an issue, which doesn't need to be. 11.82 is only correct for CEN56 S&C with 1432mm gauge and 70mm rail head. When NR60 plainline is considered (1438mm gauge and 72mm rail head) the constant changes to 11.88. The difference appears to be small but I had the issue of exceeding 100% deficiency/cant ratio in 2010 when I was working on Alexandra Palace track design. The design had been produced by another designer not to exceed the above ratio with the pway maths sheet having 11.82 embedded into the formula to calculate the equilibrium cant. Because of the speed, proposed curve radius and applied cant, the ratio was exactly 100%. However, when the cant constant was corrected for the track gauge and type in the formula, the ratio exceed 100%, which had to be justified as a variation whereas the curve radius could have been slightly modified to avoid this exceedance had the correct constant been used. Admittedly such scenarios do not happen very often.
Now with the introduction of NR60 MKII S&C suit, which uses 1435mm gauge and 72mm rail head dimension, CEN56 S&Cs will be used less often. Maybe now is the time to start updating things that were inherited.
The calculations for the cant constant are straight forward and adding it into the software will require additional parameter box to be inputted by the user; the rail gauge (or for the UK practices 11.86 for 1435mm gauge and 11.88 for 1438mm gauge could be added to the code although I would like to see the same functionality as in BRT).