Mississippi River Locks and Dams 2–10 Tow Rail System

U.S. Army Corps of Engineers, St. Paul District
Published March 14, 2016
Updated: April 15, 2024


The tow rail system is integral to the operation of each of the Mississippi River Locks and Dams 2 through 10. It is attached to the top of the lock guide wall and helps guide tows through the lock chamber. Each system is comprised of an operating unit, rail and traveling kevel or “mule.” Locks and Dams 2 through 10 tow rail systems have been deteriorating over the past several years, requiring rehabilitation of these systems.


Locks and Dams 2, 3, 4, 5, 5A, 6, 7, 8, 9 and 10.


Locks and Dams 2 through 10 tow rail systems have been deteriorating over the past several years. Two failures at Lock 7 identified the need for a project to address serviceability and safety issues. Although interim repairs at Lock 7 were completed in 2014, this project aims to repair each lock’s tow rail system for the next 50 years. Repairing the system was completed outside navigation season from 2019 to 2022 at seven locks and dams based on prioritization from condition assessments.

All sites will have the same design to ensure the navigation industry can operate the tow rail systems in the same way for commonality of components and design for standardized maintenance. The rehabilitation also ensures safe working conditions for the navigation industry as well as the lock and dam staff.


The U.S. Army Corps of Engineers’ Inland Navigation Design Center provided guidance and recommended rehabilitating the original design and incorporating a continuous rail. The Corps designed the tow rail rehabilitation at Lock and Dam 6 in fiscal year 2018, construction completed in March 2020. The Corps awarded a design-build contract for tow rail at Locks and Dams 4, 5, 5A, 7, 8 and 9 in fiscal year 2019. Construction at Locks and Dams 8 and 9 began in December 2019 and was completed in spring 2020. Design for Locks and Dams 5 and 5A was completed in fall 2020, construction began in December 2020 and completed in March 2021. Locks and Dams 4 and 7 designs were complete in spring 2021, construction began in December 2021 and completed in March 2022. Locks and Dams 2 and 3 will be addressed under a design build contract award in fiscal year 2024 or 2025.


Congress authorized the Upper Mississippi River 9-Foot Channel Navigation Project as part of the River and Harbor Act, approved July 3, 1930.


Tow rail design and construction are completed with 100% federal funds. The Corps requested $4.4 million for Lock and Dam 2 and 3 Design Build in fiscal year 2024 work plan.

FY 18 Costs:

Lock 6 Construction Contract                      $1,292,000

FY 19-22 Contract Costs:

Design-Build for Locks 4, 5, 5A, 7, 8 & 9           $20,500,000