The introduction of the first railroad in 1826 changed the landscape of America. Today, terrestrial mobile LiDAR scanning (TMLS) technology is changing the way railroads safely service the nation.

Into the 20th century, railroads expanded faster than any other industry in the country. With that expansion, the need for safety became clear. Railroad accidents involving operating employees were a serious concern, with more than 230,000 railroad employees killed and more than 2 million injured on the job from 1890 to 1970. As monitoring technologies developed and improved, there was a corresponding improvement in safety--particularly following the introduction of positive train control (PTC) in the 1990s. This technology was capable of preventing train-to-train collisions, over-speed derailments, and casualties or injuries to roadway workers operating within their limits of authority as a result of unauthorized incursion by a train. However, the installation of PTC and other safety mechanisms was largely on a voluntary basis into the early 2000s.

Then, on October 16, 2008, President Bush signed the Rail Safety Improvement Act of 2008 (RSIA - Public Law 110-432, 122 Stat. 4848-4970) to amend Title 49 of the United States Code, which addresses transportation. Introduced by Jim Oberstar, Minnesota 8th District Congressman and Chairman of the House Transportation and Infrastructure Committee, the bill mandates in one of seven titles that PTC must be installed on main line tracks by Dec. 31, 2015.

PTC systems vary widely in complexity and sophistication based on the level of automation and functionality they implement, the system architecture utilized, the wayside system upon which they are based and the degree of train control they are capable of assuming. As a result, efficiently utilizing such systems requires detailed asset inventory documentation. One increasingly popular way to gather such documentation is through the use of terrestrial mobile LiDAR scanning technology mounted on hyrailers.

The Railroad Act of 1862 put government support behind the transcontinental railroad and helped create the Union Pacific Railroad, which subsequently joined with the Central Pacific at Promontory, Utah, on May 10, 1869, and signaled the linking of the continent. Terrametrix TMLS technology and the StreetMapper 360 system is shown in the foreground.

A Challenging Route

In 2009, Bartlett & West was contracted by BNSF Railway Telecommunications to document a rail corridor in California. The telecommunications team needed to reduce the number of site visits to plan a utility line as well as eliminate change orders during the construction of the line. The scope was to collect survey-grade submeter data and corresponding color images of 84.39 miles of existing track.

Ranked among the top design firms by the industry, Bartlett & West has an extensive history of servicing railroads. Through its GeoInfo Division, based in Topeka, Kan., and Fort Worth, Texas, the firm has been designing, converting, integrating, building and implementing GIS environments in the railroad industry since 1990. However, for the BNSF Railway Telecommunications project, the firm wanted to go beyond its traditional level of service.

Allan Pickering, PMP, GISP, project manager at Bartlett & West, and other company managers had been closely following developments in mobile scanning, and they believed this was the ideal project to introduce this state-of-the-art documentation technology. “Normally, the planning of a utility along the railroad corridor involves a number of site visits to evaluate the ground truth,” Pickering says. “Combine that with the expense of numerous change orders during construction, and the need for a 3D model becomes clear. That model starts with complete data, not simple photos or video.”

The project route included one of the most difficult rail areas in the United States--the Cajon Pass. Fred T. Perris, chief engineer of the California Southern Railroad (CSRR), surveyed the first route through the pass in 1883. The first line, between San Bernardino and Barstow, was completed on Nov. 9, 1885. It runs at elevation 4,190 feet and is traversed by I-15 and portions of Route 66 near San Bernardino County, Calif. Its 3 percent grade, compliments of the San Bernardino Mountains/San Gabriel Mountain Range, is especially challenging for long trains, making the westbound descent potentially dangerous.

Bartlett & West was familiar with Terrametrix and its work using the StreetMapper 360, which combines two Riegl VQ250 2D scanners with closely coupled GPS and IGI’s IMU navigation systems as well as high-definition imagery. With traditional airborne LiDAR, Bartlett & West would have been able to capture between 60 to 80 points per square meter of data over this stretch of railroad. Using the StreetMapper 360 system and Terrametrix support, the firm would be able to capture a substantially higher data density--up to 10,000 points per square meter. “We saw the value in Terrametrix, not only with their experience in documentation but with the complete survey-grade accuracy of the StreetMapper 360 system,” Pickering says.

Terrametrix StreetMapper 360 mounted on a hyrail vehicle collecting data on a California BNSF rail line.

Complete Data in a Single Pass

To capture the required data, the StreetMapper 360 system was installed on a hyrail vehicle. Installation was completed in just two hours, and the data capture effort began. Five and a half hours later, Bartlett & West and Terrametrix had completed documentation of the 84 miles of railroad, generating 1.2 TB of color imagery and 133 GB of LiDAR data. “I have surveyed thousands of miles of railroad during my career as a surveyor,” says Michael R. Frecks, PLS, president of Terrametrix. “Using traditional survey methods, GPS and total stations, it took years to collect railroad features. The ability to document a complete snapshot in a single pass at 40 miles an hour is powerful.”

Elements that were captured in the BNSF Railway project included alignment, top of rail profile, crossings, features and asset inventory, bridges and tunnels, and terrain. QA/QC checks showed an accuracy of 4 cm throughout the challenging levels of GPS provided by the San Bernardino Mountains/San Gabriel Mountain Range.

What’s more, the technology vastly improved the safety and efficiency of the survey operation. Traditional railroad surveys require flagmen when fouling the track, which is time consuming to the surveyor and disruptive to rail traffic. Using mobile LiDAR reduced both costs and safety risks by minimizing the survey effort to capture the required data. “Coordination between the dispatcher, roadmaster, and Bartlett & West allowed the project to progress smoothly,” says John Arnold, scan technician and project manager for Terrametrix. “Traffic on the second track proceeded without interruption, and the speed at which we collected allowed us to clear the track with minimal interruption.”

The final post-processed scan data were sent to Bartlett & West’s GIS team. Using Esri’s ArcGIS software with the LP360 extension, the team was able to complete feature extraction and generate the final deliverables in less than 80 hours. “Even with the complications of learning new software and dealing with very large files, our team pulled all pertinent features from the point cloud into GIS and attributed them,” Pickering says. “This gives the end users a map context for examining the LiDAR data.”

Answering the Call

As America’s aging railroads face increasing traffic loads, they must also confront daunting maintenance requirements. Projects that ensure quality, safety and sufficient capacity are prioritized. Each rail construction task requires reliable survey data; however, interruptions in service to gather these data must be kept to a minimum. Worker safety is paramount.

TMLS is a viable solution that answers the call for safer rail documentation and updated dispatch interoperability efforts of technologies based management systems. Not since the 1940s, with the introduction of the Alco RS-2 and the Union Pacific Challenger locomotives, has there been such advancement in railroad safety and sheer power.

Sidebar: Rail Safety Improvement Act of 2008

According to the Federal Railroad Administration (FRA), there are currently 11 different PTC projects in varying stages development and implementation. These projects involve nine different railroads of various classes in at least 16 different states and cover more than 4,000 track miles. These pilot projects are not only allowing railroads to continue to advance the various technologies used to implement PTC systems but are providing the railroads valuable experience on installation and test procedures required to meet the 2015 deployment completion date.

In addition to mandating PTC by 2015, the Rail Safety Improvement Act of 2008 reauthorizes FRA, the agency overseeing the rail safety program that expired in 1998, and provides $1.65 billion for the nation’s rail safety program for fiscal years 2009 through 2013. It also clarifies that the primary mission of the FRA is to ensure safety on the nation’s railways, creates a new chief safety officer and provides resources for an additional 200 safety and rail inspection employees. The safety part of the bill was toughened in the wake of the Sept. 12, 2009, Metrolink freight train crash in the Los Angeles Basin that killed 25 people.

StreetMapper 360 TMLS point cloud data captured in a single pass at 40 mph.

Sidebar: A Class Act

Class I carriers comprise only 1 percent of the number of U.S. freight railroads, but they account for 70 percent of the industry’s mileage operated, 89 percent of its employees, and 92 percent of its freight revenue. Class I carriers typically operate in many different states and concentrate largely on long-haul, high-density intercity traffic lanes. There are seven Class I railroads: Union Pacific Railroad (UP), Norfolk Southern Railway (NS), CSX Transportation (CSXT), The Burlington Northern and Santa Fe (BNSD), Canadian National (CN), Kansas City Southern (KCS) and BNSF Railway (BNSF).

BNSF operates one of the largest railroad networks in North America, with about 32,000 route miles in 28 states and two Canadian provinces. The railway is among the world’s top transporters of intermodal traffic, serves more grain-producing regions than any other railroad, transports the components of many of the products we depend on daily, and hauls enough low-sulfur coal to generate about 10 percent of the electricity produced in the United States.