Calculation Parameters and Formulas

Abbreviations used

• • Hp = Platform design height from reference track

  • Ao = Horizontal platform design distance from reference track

  • Ai = Horizontal offset distance of platform edge of inner side in curve

  • Ay = Horizontal offset distance of platform edge of outer side in curve

  • Hi = Platform edge height of inner side in curve

  • Hy = Platform edge height of outer side in curve

  • Kir = iR = Horizontal incremental of inner side in curve

  • Kyr = yR = Horizontal incremental of outer side in curve

  • Kp = Curve point

  • OB = Start of transition

  • OE = End of transition

  • SS = Switch stock rail

  • h = Cant / Superelevation

  • X = Varies distance on transition

  • L = Length of transition

General parameter

Figure 1 show the general parameters of platform edge design. All parameters are the offset distance that reference from designed centreline of platform edge.

The distance from the reference track (positioned by default in the middle of the rails) is calculated using the following formulas:

Ai = Ao + Kir = Ao + iR

Ay = Ao + Kiy = Ao + yR

Platform edge formulas in different case

Track without Cant

• Hi = Hy = Hp  (when no cant/superelevation)

On a straight section

• Ai = Ay = Ao

In curve section

In the case of straight and curve sections without cant the height of platform is constant with Hp. Calculation of the horizontal increments for platforms at the inner or outer side is based on the following parameters and formulas:

• Ay = Ao + Ky = Ao + yR

• Ai = Ao + Ki = Ao + iR

The horizontal increments, Kir and Kyr, are defined by a theoretically carriage with length 24.0m, and axle base 18.0m. The curve increments for curves with R >180.0m can then be calculated with the following formulas:

• • Kir = iR = 81000 / (2*R)

  • Kyr = yR= 63000 / (2*R)

Track sections with transitions

In case of transition sections, the horizontal offset will increase/decrease on this section depending on the length of transition curve. The formula of platform edge is:

• Ki = (L + 10 - x) / ( L + 10) * Kir [mm]

• Ky = (L + 15 - x) / (L + 10) * Kyr [mm]

Track with Cant

In the case of curve or transition section the height of platform is varying with Hi/Hy. The formulas of horizontal offset of inner and outer side and Hi/Hy of platform are:

• Ai = Ao + Ki + (h / 1500) * Hp [h in mm]

• Hi = Hp - 0.63 * h - (h / 1500) * Ki [h in mm]

• Ay = Ao + Ky - (h / 1500) * (Hp - 375) [h in mm]

• Hy = Hp + 1.63 * h - (h / 1500) * Ky [h in mm]