MTA East Side Access

Project Overview

New York’s East Side Access project is designed to bring the Long Island Rail Road from Queens to Grand Central Terminal in Manhattan. Because the project involves tunneling under high value real estate, designers specified that the route be closely monitored for possible settlements.

Monitoring Challenges

The selected locations for monitoring, busy streets and sidewalks, presented significant challenges for installation, power, protection, and data retrieval.


GEO-Instruments met these challenges with its WMPBX mulitpoint borehole extensometer (W for Wireless) paired with its unique Lid Link® antenna.

Minimized Disruption

The WMPBXs used fiberglass rods and groutable anchors, so it could be preassembled, coiled, and shipped to the site, ready to install in a pre-drilled borehole. This minimized disruption on the busy streets.


The issue of power was addressed by the use of custom-configured, long-life battery packs, purpose-specific data loggers, and rugged, low-power displacement sensors.


These components, together with a radio module, were sealed in a waterproof, stainless steel cannister and installed below grade. This solved the protection issue.

Wireless Data Retrieval

Wireless data retrieval was made possible by the Lid Link® module, which is a traffic rated, flush mount antenna. A secure GEO-Instruments server retrieved readings from each WMPBX via the web, and forwarded them to the owner’s project data management system for review in near-real time.

MTA East Side Access Tunnels

MTA East Side Access tunnels


Installing a WMPBX

MTA East Side Lid-Link

Lid-Link® antenna transmits measurements from the well-protected MPBX below