About Amerisurv| Contact    
Magazine | Newsletter    
Flickr Photos | Advertise    
HomeNewsNewsletterAmerisurv DirectoryJobsStoreAuthorsHistoryArchivesBlogVideosEvents
 
advertisement


Subscriptions
Software Reviews
Sponsored By

Continuing Series
     RTN
An RTN expert provides everything you need to know about network-corrected real-time GNSS observations.
Click Here to begin the series,
or view the Article PDF's Here
76-PageFlip Compilation
of the entire series
Test Yourself

Got Answers?
Test your knowledge with NCEES-level questions.
  Start HERE
Meet the Authors
Check out our fine lineup of writers. Each an expert in his or her field.
Wow Factor
Sponsored By


Product Reviews
Partner Sites

machinecontrolonline 


lbszone.com

GISuser.com

GeoJobs.biz

GeoLearn

 

Spatial Media LLC properties

Associates

ASPRS

newsnow 

Home arrow Archives   The American Surveyor     

LiDAR Hits the Rails Print E-mail
Written by Larry Trojak   
Friday, 23 August 2013

A 2.656Mb PDF of this article as it appeared in the magazine—complete with images—is available by clicking HERE

Much like the apps that proliferate on our smart phones today, LiDAR is one of those technologies for which the possibilities seem, quite literally, endless. Already proven in a host of survey and construction-based operations, LiDAR has also proven its value in peripheral applications such as mining/aggregate inventory, forensic work, utility line inspection, GIS data gathering, and more. To that list, thanks to an ongoing project for the Wisconsin & Southern Railroad (WSOR), you can now add rail line clearance inspection. As part of a bridge maintenance program TerraTec Engineering, LLC (TerraTec) recently wrapped up the scanning of more than 570 miles of WSOR track using an IP-S2 LiDAR-based scanning system from Topcon Positioning Systems. When the full project is complete, TerraTec will present the railroad with a comprehensive database of potential clearance conflicts, as well as a point cloud scan of the full route (along with corresponding photo documentation) allowing the railroad to improve its shipping and maintenance efforts.

Progressive Rail Industry
For many, railroads conjure up mental images of a stodgy, passé form of transportation utilizing outdated technology. In actuality, however, the rail industry is quite progressive, using everything from ultrasonic sensors to detect cracks in wheels, to onboard GPS for fleet navigation and tracking. So, according to Jeff Francis, co-owner and principal with Cedarburg, WI-based TerraTec, it should not be surprising that, when soliciting bids for companies to play a key role in their bridge maintenance program, WSOR insisted that the effort include LiDAR-based technology.

"The railroad had a very definite plan in mind when they set out to do this," he said. "They wanted proposals for a bridge management project and we won the bid as a sub-consultant to Graef USA, the prime on the job. The overall project is to rate, evaluate and create a management plan for their bridge system, but a major component of it specified that the company chosen had to scan the bridges and the corridor for clearance purposes."

TerraTec responded to those needs with Topcon's IP-S2 LiDAR-based mobile scanning system which they leased from the Waukesha, WI branch of Positioning Solutions Company (PSC). Other choices available to them included the IP-S2 HD which offers a high-density, long-range LiDAR sensor for maximum visual mapping detail, as well as a host of advanced positioning and mapping features.

"We were confident that the IP-S2's range of features, including the Ladybug camera technology it offers as standard, were an ideal match for the project at hand," said Francis.

Scanning Rationale
While LiDAR scanning is not something the WSOR normally does, Francis said they requested it to help them better understand the clearance envelope within their network.

"The long-term goal for the railroad was simple: if a shipper calls them with a load size, they want to be able to input that information into a database and immediately be able to determine where conflicts on the system might occur. They felt that scanning was the best way to start making that happen. We took it a step further and proposed creation of a database into which they would be able to input a load parameter to determine where--based on our scanning sessions--their choke points or conflicts would be."

According to Francis, a common choke point on a railroad might be a bridge or other structure that is hard to manipulate or modify without some major investment. There are, however, many conflicts on the line that can be easily resolved--vegetation growth that can be cut, signals that can be relocated at crossings to widen clearances, posts or mile markers that can be relocated, etc.

"We typically think of a railroad as a boxcar or flatcar with a standard size width," he said. "But railroads do, in fact, carry some unique loads at times. Here in Wisconsin, wind turbine blades and towers are frequently being shipped and, because of their unique size, the railroad needs to know where on the system that load will be clear and free of the risk of damage. This will allow that to happen for the WSOR."

Making Tracks
With the IP-S2 leased from PSC, mounting the system onto a rented Ford F-250 hi-rail vehicle was the next challenge. According to TerraTec's Bob Schmalzer, PSC had a vehicle rack and mounting system that they've been using and shared that design with them. Because TerraTec's vehicle was a rental, however, permanent changes couldn't be made to accommodate the rack as designed.

"We were able to take that design, use it as a guide and create a new rack design with a mounting plate and mount it to the rental without damaging the vehicle at all."

Scanning itself was done in two phases. Schmalzer (accompanied by a pilot supplied by WSOR) first rode the entire network to establish control points on bridge structures and at crossings.

"During that pre-scan run, we also magnet-mounted a GPS unit onto the center of the truck's hood and, working through the WISCORS Network, collected a centerline, top of rail point at 100-ft intervals," he said. "By doing that, when we came back to do the actual scan, we could run two 20-mile segments using a static GPS station point within that line. And, because we were scanning those control points, we could then tap back into them during post-processing."

The 20-mile daily scan segments to which Schmalzer refers, were often dictated by train movements for that particular day, as well as where the railroad had rail car storage, and other needs the railroad might have had that day. "There were even times when we came upon a train that had stopped on the tracks because the train's crew had timed out," he said. "So we'd have to get off the tracks, leave that section, re-rail past the stopped train, and come back to scan the missed part another day. In such cases, having the railroad pilots, onboard with us was a real help."

IP-S2 Anatomy
The IP-S2 used by TerraTec consists of three high-resolution LiDAR scanners to generate a 3D point cloud that captured everything the hi-rail vehicle encountered as it rode WSOR's rails. The system runs on a cab-mounted laptop into which all the data is collected and stored.

The IP-S2 control unit has multiple sensors and a dual-frequency GNSS receiver that tracks both GPS and GLONASS signals to maximize positioning by determining the vehicle's position and attitude on a real-time basis. Vehicle wheel encoders compare rotation speeds, improving positioning accuracy even further.

The Ladybug camera system, which Francis sees as a key component of the whole package they will present to WSOR, captures 360° digital images at a rate of six pictures every three meters. The images are then stitched together in post-processing to produce a spherical street level-type photo that can be accessed in conjunction with the point cloud data.

"In addition to the database itself, we will also provide WSOR with data that we've gathered, along with Spatial Factory software viewer," said Francis. "With these, they can then go through the Ladybug photos at their office--essentially walking their entire system--and be able to visually see the conflicts that are called out in the database and determine how to best address them: `Do we move the fence post?' `Should we cut the tree down?' `Do we reposition the sign?' From that point, it will be a simple matter to create work orders and dispatch crews armed with photos and imagery to help them in their effort."

At Day's End
Post-processing data for hundreds of miles of track is, obviously, an intensive undertaking. Francis estimates that, for every hour of scanning completed, an equal hour of time is being taken to run the data through Geoclean, the Topcon software bundled with the IP-S2 that handles all the data processing.

"Geoclean takes the various types of data gathered by the satellites, the Ladybug camera, and so on, and brings it all together to create one unified subdirectory. That subdirectory, in turn, is what we access via Topcon's Spatial Factory to pull out the features we need. We really like the fact that, coming out of Spatial Factory, we can view the data in a number of different ways, including on a background Bing-type map, in a 3D format, or in a panoramic view."

The last bit of processing will include the use of TopoDOT, a CAD-based application from Certainty 3D which will allow TerraTec to further manipulate the data and generate the database which will be turned over, along with the scanning data, to the railroad.

Scanning in Their Future?
Francis said the WSOR project has been extremely successful, and even with 14-hour days, has been an interesting departure for them. They also found that, despite being the powerful tool that it is, the IP-S2 was extremely easy to use.

"Once we learned the basics, it essentially became a plug-and-play system for us," he said. "For each outing, we would get it mounted on the truck, connect the cables, hit `Run,' let the satellites configure themselves, do a two-hour scanning session--just to keep file sizes manageable--close that down, and start the next run. The whole process was very smooth.

"We see a real long-range value in other industries for which clearance issues are a concern. This is one of those tools for which new uses will continue to arise and we now have the experience under our belts to gain a competitive edge."

Larry Trojak is a communications writer for his own firm, Trojak Communications, in the town of Ham Lake, Minnesota. He is a frequent contributor to construction and survey magazines.

A 2.656Mb PDF of this article as it appeared in the magazine—complete with images—is available by clicking HERE

 
< Prev   Next >

 American Surveyor Recent Articles
Editorial 
Thought Leader: How Good is Good Enough?
We are constantly confronted by new conceptual expressions. Some are merely expressions of enduring practices or Ideas, like "environmental pollution load," which is a fancy way of quantifying a condition of unacceptable things like dirty water and air. The term "spatial analysis ....
Read the Article
Survey Locales  
Survey Locales
Well here it is ...fall in the Alaska wilderness, beautiful, pristine, and peaceful, Until a 1,000 lb. grizzly comes charging out of the bushes to spoil the moment. I'm not much a fan of working in bear country but I'm working in it most of the time. I just prefer ....
Read the Article
Wendy Lathrop, PS, CFM 
Vantage Point: Bridging the Digital (Flood Data) Divide
The first Technical Mapping Advisory Council (TMAC) to FEMA noted in its very first report (1996) that embracing the digital environment would improve efficiency in generating, managing, integrating, and distributing flood data. The National Research Council's 2009 report, "Mapping the Zone: ....
Read the Article
Michael J. Pallamary, PS 
Curt Brown Chronicles: The Challenging Future for the Land Surveyor
The purpose of a closed book examination is to test a person's knowledge of common, well-known laws of science, mathematics, techniques, and other fundamental areas of knowledge that should be recalled purely from memory. If trigonometric functions or other constants are necessary in solutions ....
Read the Article
Chad & Linda Erickson 
Firestorms & The Surveyor
After an early and hot spring, a hotter summer, and the moisture content of live trees dropping to 50%, from August 10th to the 24th of this year our community of Woodland, Idaho was literally surrounded by wildfires. From our home, the fires were ....
Read the Article
Larry Trojak 
Risky Business
In utility installation, when the most direct route from Point A to Point B is not do-able because of an impediment--a structure, a road, a stream, etc.--contractors in that field most often turn to horizontal directional drilling (HDD). This technique uses ....
Read the Article
 Maune And Horner 
Denali (Mount McKinley) Elevation Campaign
In August 30, 2015, U.S. Secretary of the Interior Sally Jewell announced that the highest mountain in the United States and North America, formerly known as Mount McKinley, would be officially given the traditional Koyukon Athabascan name of Denali. This announcement was the culmination of ....
Read the Article
C. Barton Crattie, LS, CFM 
Rendezvous 2015: Surveyors of the Salish Sea
Just think of the United States as a big old box or rectangle if you will, at least the United States of the first five years of my life. No Alaska, no Hawaii. Going clockwise from the upper right, Maine. The lower right, sunny Florida. Move to the left and there's ....
Read the Article
Eric Stahlke, PS 
The Final Voyage - Part 6
Our grand plan for the summer was coming together at last. While the Seloohge was working its way up the Koyukuk River towards Hughes, TCC's other survey crews were putting in townships with a helicopter in the distant Kanuti River highlands, staying at a pipeline era truck stop on the ....
Read the Article
Jason E. Foose, PS 
The HP 35s Calculator: Linear Equations and Land Development
Linear equations are powerful solving tools especially when unleashed from classroom confines of counting the number of legs on chickens and cows. We can utilize systems of linear equations for many applications like solving intersections, estimating project supplies, and in this case land ....
Read the Article
Dave Lindell, PS 
Test Yourself: Unusual Curve Formulae
Show that TAN D = E and COS D = ??? Dave Lindell retired after 36 years with the City of Los Angeles. He keeps surveying part time to stay busy and keep out of trouble. For the solution to this problem (and much more), please visit our website at: www.amerisurv.com. Good luck! ....
Read the Article
Feedback 
FeedBack
Without question the vast majority of land transactions in Arizona are executed without the presence of visible property corner monuments, placing the buyers at great risk of litigation and loss. Because we can only think in terms of full surveys, the survey profession is as guilty as any for ....
Read the Article
Michael J. Pallamary, PS 
Angle Points: Smoots and Anchors
I enjoy the use of the English language, especially with regards to writing and communication. As Land Surveyors, we employ a broad range of terms, some common and some not so much. Indeed, one of my greatest pleasures is reworking words and phrases into a tangible way of communicating. This ....
Read the Article

deliciousrssnewsletterlinkedinfacebooktwitter

Amerisurv Exclusive Online-only Article ticker
Featured Amerisurv Events
List Your Event Here
please
contact Amerisurv


Google
 
AMERISURV TOP NEWS

Educator Dave
Gibson Passes

GOT NEWS? Send To
press [at] amerisurv.com
Online Internet Content

Sponsor


News Feeds

 
Subscribe to Amerisurv news & updates via RSS or get our Feedburn
xml feed

Need Help? See this RSS Tutorial

Historic Maps
Careers

post a job
Reach our audience of Professional land surveyors and Geo-Technology professionals with your GeoJobs career ad. Feel free to contact us if you need additional information.

 

Social Bookmarks

Amerisurv on Facebook 

Amerisurv LinkedIn Group 

Amerisurv Flickr Photos 

Amerisurv videos on YouTube 

twitter

 




The American Surveyor © All rights reserved / Privacy Statement
Spatial Media LLC
905 W 7th St #331
Frederick MD 21701
301-620-0784
301-695-1538 - fax