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


Subscriptions
LiDAR Webinar
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 

LiDAR News

symbianone
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For many, railroads conjure up mental images of a stodgy, passé form of transportation utilizing outdated technology.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 
Editorial: Watchman on the Wall
In this issue we have Dick Elgin's open letter to NCEES which details why the proposals before us are bad ideas. We also have the NCEES response to my Fire Alarm editorial. Lately we've been asked why we are devoting so much coverage to the licensure experience requirement when many say ....
Read the Article
Dick Elgin, PhD, PS, PE 
Open Letter: Regarding NCEES and Survey Licensing
I thank the Council for its many years of work assisting state boards, preparing exams and for generally advancing the surveying profession and contributing to protecting the public. Your stated missions are worthy. However, as stated in the Council's December, 2014 "Exchange," ....
Read the Article
Wendy Lathrop
Vantage Point: When Flooding Leads to Creativity
Sometimes a disaster is the best wake up call and the prod that moves us forward from "same old, same old" practices. About 15 years ago, a colleague once noted ruefully that the best check of a Flood Insurance Rate Map's accuracy is to have a disaster: did the map predict the horizontal ....
Read the Article
Michael J. Pallamary, PS 
The Curt Brown Chronicles: Similarity of New Zealand and U.S. Laws
Within the United States it is a well established fact that old possession can stand as a monument to the original lines as marked and surveyed by the original surveyor. Fences built soon after section lines were run might stand as proof as to where future the original lines were run, especially after ....
Read the Article
Chad & Linda Erickson 
One-Room Schools, Aerial Photos, & Hokey Pokey Surveys
We found a blurb about the Idaho State School Board in the 1900's making the decree that sunlight coming over the left shoulder made the students more intelligent, or something like that, and all windows in one-room schools had to be moved ....
Read the Article
Smith, Roman, Youngman 
Recent Activities at the National Geodetic Survey - Part 3 of 4
The advent and evolution of new technology such as Global Navigation Satellite Systems (GNSS) over the last thirty years has allowed NGS, other Federal, State and Local Agencies, and the Private Sector to determine geodetic positions with greater speed, better accuracy, and less ....
Read the Article
Michael J. Pallamary, PS 
U.S. Supreme Court Introduces Confusion and Conflict
On December 15, 2014, the United States Supreme Court issued a decree in the hopes of settling a decades-old dispute over the location of California's offshore boundary, a line common with the United States of America. The conflict originated in 1946 ....
Read the Article
Brynna King 
Tunnel Vision - Excavating Subsea Roadways
Workers who blast tunnels 290 meters below the ocean's surface have plenty of "what-ifs" to consider. Technology failures and project budgets shouldn't be among them. So contractors working on Norway's Ryfast tunnel megaproject are using ....
Read the Article
 Mark Silver 
Geodetic Preppers - Surviving the Next OPUS Disaster
I don't have any inside knowledge if the US government is going to shut down again this year. But I do know if there is a shutdown like there was in October 2013 I am going to have a hard time grounding surveys without the National Geodetic Survey's OPUS products. One never knows what the ....
Read the Article
Jason E. Foose, PS 
The HP 35s Calculator - A Field Surveyor's Companion: Part 6 - Curve Traverse
This program is a curve traverse routine based upon the traditional methods of laying out a curve with a transit and tape. I assure the users of radial layout equipment and GPS that using this program is 100% compatible ....
Read the Article
David H. Widmer, PS 
Open Letter: Response to The Fire Alarm
The purpose of my letter is to dispute some information contained in your editorial mentioned above. First off, NCEES has absolutely nothing to do with any proposed legislation in Idaho to do away with experience prior to licensing. That goes against our three legged stool test of education ....
Read the Article

deliciousrssnewsletterlinkedinfacebooktwitter

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


Google
 
AMERISURV TOP NEWS

New PointFuse
Pro Announced

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