CP Uses Laser Survey to Finalize Annual Maintenance Program

Field, Canada May 2009

Business Challenge

The “Spiral Tunnels” is a section of mainline track operated by Canadian Pacific Railway (CP) and is located on the Provincial borders of Alberta and British Columbia in Banff National Park. This impressive section of track consists of several small tunnels and two major tunnels (Spiral Tunnels) which double back on each other to maintain a consistent track grade through an avalanche prone region.

Due to frequent ground movements, icing and other natural occurrences, the interior tunnel walls are exposed to a variety of elements that can affect their stability. CP needed to know to what extent the tunnel walls could pose a risk to the safe passage of trains and what remedial works, if any, might need to be included in its annual maintenance program. With competing priorities for infrastructure maintenance spend, CP was hoping that funds could be directed to other urgent projects and requested GT’s help in assessing the tunnels so that the appropriate budget allocations could be made.

Services Overview

Geomatic Technologies (GT) offered to undertake a laser clearance survey of spiral tunnels section, which included the tunnels and the approaches between them. GT’s AIMS Laser Clearance system was flown out to Calgary from Rochester, NY, and mobilized onto a CP Hi-Rail vehicle. Within hours of the equipment arriving on site, continuous laser, imagery and positional data was recorded of the section.

During office processing, a precise track centerline was generated and the recorded data was integrated with this centerline. This allowed for accurate positioning, identification and validation of all infrastructure assets along the recorded section, including Mile Post markers, bridges, turn-outs and each spiral tunnel.

Precise positioning through the tunnels allowed GT to create an accurate track alignment. The laser data was then combined into discrete alignment sections for all tangent track, curved track and transition curved track and a “minimum laser profile” or composite profile for each discrete alignment section was generated.

The resulting report highlighted one section of tunnel that troubled CP, so further analysis was undertaken. Individual profiles were generated every 50 feet along this section and an on-site inspection showed that some of the tunnel lining had become loose. Finally, the laser profiles highlighted some new infrastructure (equipment enclosures) that had been installed in the tunnels, but which were unknown to the Clearance Department. This information allowed them to update their clearance information through the tunnels.

CP was able to quickly determine that no remedial works were required in the tunnels so that funding could be allocated to other more urgent infrastructure needs.

Outcomes

• GT’s quick mobilization and execution ensured that CP could finalize its annual maintenance program without the delays otherwise associated with conventional terrestrial surveys.
• Repeat processing of the continuous laser data delivered further benefits to stakeholders demonstrating that continuous laser data surveys offer superior value to clients.
• Delays to railroad operations were minimised as data was collected at ‘line speed’.
• Any potential encroachments could be accurately located for easy on site verification due to the precise positioning information collected during the survey.

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