1 rich Libsyn https://www.libsyn.com 90 600 Sean Johnson has a keen eye out for movement and unforeseen changes at the HRBT Expansion Project.&amp;nbsp;In this installment of HRBT Tunnel Talk, hear Sean explain how he relies on “invisible” measurements to help detect changes in and around the construction environment. HRBT Tunnel Talk http://hrbtexpansion.org/ <iframe title="Libsyn Player" style="border: none" src="//html5-player.libsyn.com/embed/episode/id/36057195/height/90/theme/custom/thumbnail/yes/direction/forward/render-playlist/no/custom-color/88AA3C/" height="90" width="600" scrolling="no" allowfullscreen webkitallowfullscreen mozallowfullscreen oallowfullscreen msallowfullscreen></iframe> https://assets.libsyn.com/secure/content/186788155