Ottawa Lite Rapid Transit Line

Tunnelling

Scope of Supply

NLT provided a wireless communications and tracking solution for the tunnel portion of Ottawa’s new Confederation Lite Rapid Transit Line (OLRT). The Confederation line will eventually extend over 40 kilometers, generating approximately $16 million in annual operating savings and reducing the city’s diesel consumption by 10 million liters per year.

Site Detail

Phase one of the OLRT project is a 12.5 kilometer section that includes a 2.5 kilometer tunnel under the downtown core. The tunnel has been broken down into three construction sites: east, west, and centre shaft. Each tunnel section has its own Sandvik Road header tunnel boring machine and supporting crew while being excavated.

Project Challenges

All activity at the three construction sites needed to be monitored simultaneously at the Project Command Centre in the West Portal. The tracking data from the three portals was transmitted to the Command Centre via dedicated DSL lines and routed through the Internet Service Provider (ISP).

NLT was originally expected to commission all three sites at one time. Due to construction delays, NLT was required to do two site visits, and the third site was commissioned by OLRT staff.

NLT experienced a number of challenges attempting to integrate third party nodes purchased by OLRT into the system in order to extend Wi-Fi on the surface around the three portals. When it was discovered that the issues with the tracking and Ranger phone performance related back to the third party nodes, these access points were taken out of service.

Project Details

The original scope of work required the following equipment be deployed:

  • Line powered 2-radio/2-fibre port nodes with battery backup, and internal heaters, installed at each of the three portal entrances
    • Using two radio nodes maximized Wi-Fi coverage while minimizing the number of nodes required
    • Two radio nodes also allowed monitoring of the direction of tracked traffic into or out of the tunnel
    • Battery backup was required to maintain system integrity during the frequent power outages experienced on site
    • The ambient temperature in the tunnels drops to well below zero in the winter, requiring internal heaters to be installed in the nodes
  • An additional two NetPorts were spec’d for installation due to the curvature of the tunnel, which affects line of site coverage
  • 2 radio/2 fibre port compact nodes were installed on each of the three Sandvik Road headers, connected to the onboard computers via Ethernet cable
    • These nodes are used to wirelessly transmit production and maintenance data from the road headers
  • 30 Ranger VoIP phones

The Ranger phones were selected over traditional two-way radios so senior personnel can remain in constant contact across the entire three-portal construction site. Accomplishing this with two-way radios would have been cost prohibitive, since it required the installation of repeater towers. The Ranger phones are connected to the site PBX allowing direct dialing offsite. Personnel and assets are tracked using 50 Aeroscout Wi-Fi Tracking Tags.

The OLRT also requested the following be added the following to their original scope of work:

  • Longer antenna cables were installed to address signal overlap issues with the two radio nodes at the portal entrances
  • The road headers were experiencing power outages, so the compact nodes were replaced with NetPorts with battery backup
  • The original road header compact nodes were redeployed on the surface at the three portals, replacing the third party’s (out of service) nodes and extending Wi-Fi coverage
  • The addition of 30 phones and 100 Aeroscout tags
  • Noise-cancelling headphones with boom mics to be used with the Ranger phones on the road headers
  • Two Wireless Input Output Devices (WIODs) with Conspec Smart Heads were installed to trial NLT’s automated gas monitoring solution