Home » railML newsgroups » railml.rollingstock » Different ways to model tractive effort (How to enter discrete, hyperbolic or quadratic tractive effort curves?)
Re: Different ways to model tractive effort [message #2158 is a reply to message #2156] Tue, 05 March 2019 14:20 Go to previous messageGo to previous message
Thomas Nygreen JBD is currently offline  Thomas Nygreen JBD
Messages: 68
Registered: February 2017
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Dear all,

The current railML2 valueTable could support any of the segmented functions listed by Laura and Jörg, if we for each row apply the formula
F = Sum ( y_z * v^z ) for all z

where each value for z is given by columnHeader@zValue.

If no column header is found and only one column is given, we would assume z = 0, meaning that F = y. This allows programs to keep listing the tractive effort for small speed steps.

This approach would support any polynomial function, such as constant (only z=0), linear (0 and 1), quadratic (0, 1, 2) and cubic (0, 1, 2, 3), the simple hyperbolic (-1, 0) and quadratic hyperbolic (-2) listed by Laura and Jörg, and other simple rational functions where there is no shift of the x variable.


Best regards,
Thomas Nygreen
Railway capacity engineer
Jernbanedirektoratet
 
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