Switch-Lead SL Calculator

Switch Lead Formula:

\[ SL = \sqrt{2 \times R_0 \times d} \]

Switch Lead (SL): m

1. What is Switch Lead (SL)?

Definition: Switch Lead is the distance between the tangent point and the heel of switch measured along the length of the main track.

Purpose: It's a critical measurement in railway track design that determines the geometry of turnouts.

2. How Does the Calculator Work?

The calculator uses the formula:

\[ SL = \sqrt{2 \times R_0 \times d} \]

Where:

\( SL \) — Switch Lead (meters)
\( R_0 \) — Radius of Outer Curve of Turnout (meters)
\( d \) — Heel Divergence (meters)

Explanation: The formula calculates the distance based on the geometry of the turnout curve and the divergence at the heel.

3. Importance of Switch Lead Calculation

Details: Proper switch lead calculation ensures smooth transitions between tracks, reduces wear on rolling stock, and maintains safety standards.

4. Using the Calculator

Tips:

Enter the radius of the outer curve of turnout in meters
Enter the heel divergence in meters
Specify tolerance percentage (default ±5%)
All values must be positive numbers

5. Frequently Asked Questions (FAQ)

Q1: What is typical tolerance for switch lead?
A: Typically ±5% is used, but this may vary based on specific project requirements.

Q2: How is heel divergence measured?
A: Heel divergence is the distance between the running faces of stock rail and gauge face of the tongue rail at the heel of switch.

Q3: What affects the radius of outer curve?
A: The radius depends on train speed, wheelbase of rolling stock, and turnout angle.

Q4: Can this calculator be used for any turnout type?
A: This formula works for standard turnouts, but specialized designs may require different calculations.

Q5: Why is switch lead important in track design?
A: It determines the smoothness of transition between tracks and affects both safety and ride quality.