# Branch pipe

From IBLS

A **branch pipe** conveys steam from the throttle to the input of a cylinder. Most steam locomotives have two **branch pipes** , one for each cylinder, that split off a single feed from the throttle.

## Calculating Diameter

The diameter of a **branch pipe** can be computed with the formula given below, from "A Treatise on the Steam Engine".

- The following rule gives the usual diameter of the
**branch steam pipe**for locomotive engines.

- RULE -
*To find the diameter of the***branch steam pipe**for the locomotive engine - Multiply the square of the diameter of the cylinder in inches by 0.021. The product is the diameter of the**branch steam pipe**for the locomotive engine in inches.

- RULE -

- Example - Required the diameter of the
**branch steam pipes**for a locomotive engine, when the cylinder's diameter is 15 inches. Here, according the rule, diameter of**branch pipe**is computed as:

- Example - Required the diameter of the

- branch pipe diameter = 0.021 x 15
^{2}= 0.021 x 225 = 4.725 inches

- branch pipe diameter = 0.021 x 15