Sloped Slab Screed Setup for Rail-Critical Concrete on the LAX Automated People Mover

Sloped Slab Screed Setup for Rail-Critical Concrete on the LAX Automated People Mover

Sloped Slab Screed Setup for Rail-Critical Concrete on the LAX Automated People Mover

On transit work, concrete isn’t just concrete — it’s geometry. When the slab directly supports rail infrastructure, slope and elevation control are non-negotiable.

That was the reality on Phase 1 of the LAX Automated People Mover, delivered by LAX Integrated Express Solutions (LINXS) as part of Los Angeles World Airports’ modernization program.

The placement problem: sloped slab + variable depth

This phase included roughly 100,000 square feet with slab depth varying from 8 inches to 12 inches. On a sloped placement like this — especially where rail alignment is critical — you don’t get to “make it work” with a fixed screed support approach.

The crew needed an adjustable screed support system that could:

  • hold grade across a changing section,

  • stay stable on a vapor barrier, and

  • support a mechanical screed without deflection or drift.

The MAKO solution: JAWS RailFin + FinStand + Base Plate

MAKO’s setup combined:

  • JAWS RailFin screed chairs

  • FinStand

  • Base Plate

The RailFin is built to support a ¼-inch flat rolled steel rail. For this job, the team went a step further and engineered a purpose-built T-Rail backbone to increase stiffness and provide additional support under the mechanical screed:

  • Rail: 1.5" x 0.25"
  • T-top: 1.5" x 0.25"

That “backbone” approach matters on sloped slabs. It helps control rail straightness and reduces the chance of the screed rail telegraphing movement when the screed is running.

Why it worked

This wasn’t about adding complexity — it was about controlling the variables:

  • Adjustability to chase a slope with changing slab depth

  • Stability on vapor barri

  • er using Base Plates (no punching through, no wobble)

  • Rail support designed for stiffness to keep the screed true

  • Repeatable setup over a large area without constantly reinventing the install

When slope is tied to rail performance, the “best” screed support system is the one that installs predictably, holds line, and doesn’t move when the work gets real.

MAKO’s RailFin + FinStand + Base Plate delivered the

 adjustability and stability this placement demanded — on a rail-critical slab where tolerance isn’t a suggestion.