What exactly are the two Trainz track superelevation parameters P1 & P2?

[mapsgame]

What exactly are the two Trainz track superelevation parameters P1 & P2? P1 = Superelevation Degrees and P2 = Superelevation Limit. Any one have a definitive answer from N3V?
I have been doing a research about superelevation. Its a straight forward calculation based on speed, radius, and technically track rail center line width where forces act, not the track guage. Consistency of units of measure do make a big difference so does the rail width and track gauge, i.e., track width = guage + 1 railhead width. US Customary units are typically measured as ft, mph and angles are measured in degrees. But sometimes meters are used instead of feet. Railroads in the US use the chord definition of a circular curve and superelevation is measured in inches. In Europe and Australia, International System (SI) units are meters, kph and angles are measured in radians, and superelevation is measured in mm.
Before posting this, I reviewed the N3V How To Guide on Superelevation. https://online.ts2009.com/mediaWiki/index.php/HowTo/Use_Superelevation and down loaded its spreadsheet and looked at the formulas. I have also searched the forum for superelevation posts and found other's spreadsheets on calculating superelevation and P1 and P2. P1 = Superelevation Degrees seems obvious but what units is N3V using in game for degrees? Radians or angle? P2= Superelevation Limit is not so obvious. What is it? There is no literature on superelevation limit in any railroad track design in Europe or US that I can find, so it must be a game parameter.

Just looked at the in Trains Plus. The Superelevation Limit now has a degrees symbol and its value can range from 0 to 100°. The Superelevation Degrees is entered as a decimal and can range from 0.0 to unlimited. This makes absolutely no sense.

What do you know about these to parameters? What's been your experience applying them and the result of various combinations of p1 & p2? Is it only for show? Does superelevation make a difference if derailment is set to realistic?

 

[pware]

Its a straight forward calculation based on speed, radius, and technically track rail center line width where forces act, not the track guage.

It appears that there are several different ways of calculating the superelevation. None of them seem to be "straight forward", at least from my point of view, and track gauge along with the track centre line are both included in the "calculation soup".

Here is one reference that I found - units in this document are imperial not metric.

https://www.jghtech.com/assets/applets/LFLSRM-Fundamentals-of-Railway-Curve-Superelevation-current.pdf

 

[mapsgame]

Everyone and his brother, including all the railroad authorities in every country have derived the calculations for superelevation in one form or another. Its crazy to think, but I do understand all the physics and geometry. The source you provided is one of the best I've seen. Thanks @pware ! I particularly like the "Speeds of Trains on Curve" graphs in the source you provided. They made the slide rule calculations, used back then, unnecessary. Preparing graphs like those are a lost art now that everyone relies on computers for the exact calculation to the 10th decimal place.

I found out a little more about the Trainz p1 & p2 superelevation parameters by hovering my mouse pointer over the text labels beside their entry cells in the Rail-Advanced-? dialogue box. The following comments appear that say:

Superelevation Degrees - "The degree of superelevation at this track vertex (where 0 is none and 1 is one degree bank per degree curvature)."

Superelevation Limit - "The maximum bank angle of superelevation at this track vertex."

These comments point me to certain elements of real world superelevation and rail curve data for calculating p1 and p2. I will test them visually in game next. Still wondering if game superelevation is all for show or if it actually can affect game, e.g., cabin sway, or derailment?

 

[pware]

I found out a little more about the Trainz p1 & p2 superelevation parameters by hovering my mouse pointer over the text labels beside their entry cells in the Rail-Advanced-? dialogue box. The following comments appear that say:

Superelevation Degrees - "The degree of superelevation at this track vertex (where 0 is none and 1 is one degree bank per degree curvature)."

Superelevation Limit - "The maximum bank angle of superelevation at this track vertex."

Ahhh. Thank you for that information. They have been the "missing pieces" in the documentation on the S20 tools that I have been creating.

 

[mapsgame]

Ahhh. Thank you for that information. They have been the "missing pieces" in the documentation on the S20 tools that I have been creating.

Please comment on the methodology I have developed to verify track superelevation (SE) in Trainz? The methodology uses a pavement marking spline like "Airport Marking Line Continuous 0.4m Wide", which is placed between the rails with the spline points at the middle of each rail's rail head. The Airport Line spline elevations are adjusted so the rail heads are just barely visible. On flat track the elevations of two Airport Line splines are identical. Next, input values in Trainz track spline points for superelevation Degree and Limits to achieve the desired superelevation, i.e., difference between the top of the inner and outer rail heads. These values will raise the outside rail. To measure the result, raise the pavement marking spline point of the outer rail so that the outer railhead is just barely visible again. The difference in elevations between the superelevated outer and the inner rail should theoretically approximate the superelevation in whatever units of measure you are using. Thoughts?