Rail Stress Calculator

Calculate thermal stress in continuous welded rail (CWR) from temperature change using σ = E × α × ΔT. Assess buckling and break risk.

Inputs

Neutral (stress-free) temperature

°F

Current rail temperature

°F

Rail weight

lb/yd

Tab to move between fields

Results

Thermal stress

6,825 psi

Thermal stress47.1 MPa

Axial force91 kips

Temperature change35 °F

Stress type1

Stress/yield ratio0.1

Safety factor10.26

Buckling risk level0

Rail break risk level0

Break gap (39-ft rail)0.11 in

Rail cross-section area13.33 in²

How to Use This Calculator

Enter Neutral (stress-free) temperature, Current rail temperature, and Rail weight.
Review the Thermal stress (psi) result.
Use Thermal stress (MPa) and Axial force (kips) to inform your decision.

How the result changes with Current rail temperature

Current rail temperature	Thermal stress
-20	22,425 psi
30	12,675 psi
90	975 psi
140	8,775 psi

What each input means

Neutral (stress-free) temperature: Temperature at which rail was laid with zero stress (AREMA: 95±5°F).
Current rail temperature: Current rail temperature. Rail surface can be 30-40°F hotter than air.
Rail weight: Rail section weight (common: 115 RE, 132 RE, 136 RE, 141 RE).

What each result means

Thermal stress: Axial stress from temperature change: σ = E × α × ΔT.
Thermal stress: Same stress in metric units.
Axial force: Total force in the rail cross-section (stress × area).
Temperature change: Difference from neutral temperature (positive = hotter).
Stress type: 1 = compressive (hot, buckling risk), 0 = tensile (cold, break risk).
Stress/yield ratio: Thermal stress as fraction of rail yield strength (~70 ksi).
Safety factor: Yield strength divided by thermal stress.
Buckling risk level: 0 = low, 1 = medium (ΔT 40-60°F), 2 = high (ΔT > 60°F).
Rail break risk level: 0 = low, 1 = medium, 2 = high (tensile stress in cold).
Break gap (39-ft rail): Gap that would open if a 39-ft rail section broke free.
Rail cross-section area: Estimated cross-sectional area from rail weight.

How this is calculated

Worked example, using the default values

Identify Input Parameters
Neutral (stress-free) temperature = 95, Current rail temperature = 130, Rail weight = 136 = 3 input(s) provided
Calculate Thermal stress
Thermal stress = E_psi * alpha * absDeltaT
6825 = 6825
Calculate Thermal stress
Thermal stress = E_psi * alpha * absDeltaT
47.1 = 47.1
Calculate Axial force
Axial force = thermalForce / 1000
91 = 91

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