Download TTCI report: user guide for variable charges model

Methodology to Calculate Variable Usage Charges for Control Period 4
Substituting Equations B11, B12 and B14 into Equation B6 gives15 < Tγ ≤
175 N:
Cost RCFDamage
=
× GrindingCost +
Axle
Axle
(B15)
DepthGround ⎛ RCFDamage WearDamage ⎞ RenewalCost
×⎜
+
⎟×
GrindingCycle ⎝
Axle
Axle
⎠ SideLossLimit
and finally for 15 < Tγ ≤ 175 N Equation B16:
Cost = RCFDamage × GrindingCost +
DepthGround
RenewalCost
× (RCFDamage + WearDamage)×
GrindingCycle
SideLossLimit
(B16)
For Tγ ≥ 175 N:
DepthWorn
WearDamage
=k×
Axle
Axle
(B17)
At Tγ = 175 N the depth worn per axle from Equations B14 and B17 should be
the same. Thus:
k=
DepthGround
GrindingCycle
(B18)
Substituting Equations B11, B17 and B18 into Equation B6 gives for Tγ ≥ 175
N:
Cost DepthGround WearDamage RenewalCost
=
×
×
Axle GrindingCycle
Axle
SideLossLimit
(B19)
and finally for Tγ ≥ 175 N Equation B20:
Cost =
DepthGround
RenewalCost
× WearDamage ×
GrindingCycle
SideLossLimit
(B20)
Thus, an equations have been derived that gives the cost of rail surface
damage in terms of known variables and the wear index (Tγ) generated by a vehicle.
Table B1 lists assumed values for the variables in Equation B15.
Prepared by TTCI(UK) Ltd.
‹
27 March 2008
‹
Page 70