Track undercutting provides for the removal of all fouled track ballast, which is then cleaned and returned to the track bed. When the ballast is fouled, the load spreading capability is lost. Undercutting is necessary when the ballast section has become so contaminated that normal ballasting and surfacing will no longer hold a proper track surface. The results of undercutting are a smooth, well-aligned track surface, extended tie and ballast life and reduced ongoing maintenance expense.