| lead (theoretical) | The distance from the theoretical point of a uniform turnout curve to the theoretical point of the frog, measured on the line of the parent track. |
| lead (actual) | The length between the actual point of the switch and the half-inch point of the frog measured on the line of the parent track. |
| lead curve | The curve in the turnout interposed between the heel of the switch and the frog. |
| curved lead | The length measured on the outside gage line of turnout from the point of switch to the point of frog. |
| closure rails (lead rails) | The rails connecting the heels of the switch rails with the toe end of the frog. |
| turnout number | The number corresponding to the frog number of the frog used in the turnout. |
AREA Track Definitions Home
General Terms Split Switch Terms Frog Terms Guard Rail Terms Crossing Terms