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Project Name

New Mexico Rail Runner Express Walls

Customer Name
New Mexico DOT

Design / Specifying Engineer
Terracon, Inc.; HNTB; Don MacCornack, PE, MacCornack Engineering; Steven A. Hooper, PE, Materials Inc./Buildology

Block Manufacturer
Materials Inc./Buildology

Wall Installer
Joint Venture with Kiewit New Mexico (formerly Twin Mountain Construction) and Herzog

Project Location
Belen, NM to Santa Fe, NM

Year Built
2006

Project Scope

A world-class commuter train requires world-class walls to protect the line. When the Rail Runner Express commuter train needed retaining walls and bridge abutments along the rail line, engineers chose Redi-Rock retaining wall systems for the job. Read on to find out why.

The central New Mexico corridor contains about half the state's population, with many living in Albuquerque and commuting to Santa Fe each day for work. The 4-lane interstate which connects the two cities was becoming increasingly congested, and expansion of the freeway was not feasible.

In 2003, New Mexico governor Bill Richardson was instrumental in making the new commuter train a reality. The Rail Runner Express was constructed in two phases—Phase I from Belen to Bernalillo was completed in 2006; Phase 2 from Bernalillo to Santa Fe was completed in 2008. Prior to construction, NMDOT purchased the railway from BNSF, which gave the commuter trains priority over freight trains. The Rail Runner system connects to Amtrak lines in Albuquerque.

In several places, the rail line passed above or below roadways, which necessitated bridge construction. To flank the bridges, prevent erosion and provide an aesthetic finish, the bridges required abutments. Project engineers from HNTB specified Redi-Rock, a large block retaining wall system made of precast concrete that has the look of natural stone. Redi-Rock installs easily like one-ton Lego blocks, and has the ability to build tall walls that harness the power of gravity. Even taller reinforced walls are possible.

Bernalillo-based Redi-Rock manufacturer Materials, Inc. had worked with Kiewit, the general contractor, on several projects in the past. Redi-Rock has a proven track record in bridge abutment applications. The massive scale of the system gives finished walls load-bearing capacity, as well as an attractive finish. Also, Redi-Rock walls can be built with varying setback to accommodate any site—whether it requires a zero degree batter using Redi-Rock Zero Batter blocks, a four degree batter using standard Redi-Rock blocks, or a 26.6 degree batter using 9 In. Setback blocks. All of these types of blocks are complimentary and can be used in the same wall to create a custom solution to fit a project's needs.

The engineers involved in the planning agreed that Redi-Rock was the best choice for the bridge abutments along the railway.

HNTB wanted to outsource the wall design to a New Mexico PE. Materials Inc. (MI) hired Don MacCornack, PE who has several years of experience designing Redi-Rock walls. Steve Hooper, PE with Builology worked directly with HNTB and Terracon (the project's geotechnical engineer) to evaluate civil drawings and soil information. Hooper did preliminary designs and forwarded them to MacCornack for final design and to draw the walls for the project.

HNTB liked the versatility of the Redi-Rock system, as there were several different wall configurations required for the project. In total, the project required six walls comprised of 2,164 Redi-Rock blocks or approximately 12,440 sq. ft. of retaining walls. Plus, two walls required a zero degree batter to allow them to abut box culverts and three walls required custom blocks to accommodate drainage pipe.

For the Rail Runner project, engineers designed both gravity and reinforced walls in Redi-Rock's Limestone texture. The tallest wall stands approximately 20 ft. tall.

To blend in with the native earth tones, several of the higher-visibility Redi-Rock walls were stained to blend in the landscape after construction was completed. Phase one opened in 2006 and phase two opened in December of 2008.

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