Mississippi River Locks and Dams 2–10 Tow Rail System

U.S. Army Corps of Engineers, St. Paul District
Published March 14, 2016
Updated: March 29, 2022

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 guidewall and helps guide tows through the lock chamber. Each system is comprised of an operating unit, rail and traveling kevel or “mule.”  The Locks and Dams 2 through 10 tow rail systems have been deteriorating over the past several years, requiring rehabilitation of these systems.


Construction repairs were completed in fiscal year 2020 at Locks and Dams 6, 8 and 9. Construction will occur at Locks and Dams 5, 5A in fiscal year 2021 and at Locks and Dams 4 and 7 in fiscal year 2022.


The 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 will be completed during the non-navigation season from 2019 to 2022 at seven locks and dams.

All sites will have the same design to ensure the navigation industry is capable of operating the tow rail systems in the same way. 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 and construction is scheduled to begin in December 2021 and complete in spring 2022.


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.

Fiscal Year 2018 Costs:

Lock 6 Construction Contract                       $1,292,000

Fiscal Year 2019 Contract Costs:

Design-Build for Locks 4, 5, 5A, 7, 8 & 9    $20,237,592