• Rachel Timokhina, CP&Y Blog Writer

Precision Under Pressure: CP&Y Provides Survey for Bore Beneath Railroad

Survey Technicians Troy Day and Matt Holling provided highly accurate surveys under difficult conditions to ensure the safety of construction crews, railroad employees, and project area traffic for this unusual utility relocation project.

Trimble equipment in the foreground pointing towards railroad in the background.
Trimble equipment near railroad.

About the Project

For the SH 6/Loop 340 Utility Relocation project, the City of Waco contracted CP&Y to provide relocation design, easement negotiations, bidding, construction phase services, resident project representation, permitting and reimbursement agreements.


Because CP&Y’s Survey Department created the design surveys, the utility contractor engaged with CP&Y to provide construction survey activities, which is where Troy and Matt come in.

Bore equipment.
Bore equipment.

Getting in the Zone

The relocation design of the utilities required that the contractor bore beneath the Union Pacific Railroad (UPRR) to install a metal sleeve beneath the rails. Because a significant portion of the 70-foot bore was inside the railroad’s highly sensitive Zone A, CP&Y’s surveyors were on site to keep a close eye on the vertical control of the railroad, looking for the slightest change as the contractor bored beneath.


If the tracks dropped just 1/8-inch, the CP&Y team was required to immediately notify the Railroad Engineer. If the tracks dropped 1/4-inch, then the project was to come to a complete stop. All measurements were regularly reported to both the Railroad Engineer and contractor.


To provide the highest level of accuracy during this monitoring process, Troy and Matt used fully calibrated, state-of-the-art equipment (the Trimble S5 Robotic Total Station) to take measurements that were accurate within 1/1,000th of an foot.


Our surveyors established tight control of the construction site area, using 10 adhesive targets along the rails. For increased stability, Troy and Matt set 3-foot-long iron rods in the ground to establish reliable project control, turning multiple angles, and running tight elevation bench loops.


Adhesive target sticker on rail seen through Trimble in crosshairs.
Adhesive target sticker on rail in crosshairs.

Weathering the Storm

With accurate equipment and control points established, Troy and Matt were able to provide exact measurements of the railroad’s vertical controls to 10 adhesive targets twice daily: once at exactly 8:45 a.m. and the second at exactly 3:00 p.m. As soon as the boring entered Zone A, our surveyors began taking measurements four times a day (twice during daylight hours and twice at night) for additional monitoring.


Troy and Matt tirelessly provided this level of accurate, round-the-clock monitoring despite wild, spring-time Texas weather. Rain came down sideways, and throughout difficult conditions and stormy, rough weather, our technicians were still out in the downpour taking measurements. Additionally, our team continued returning to the office to prepare the reports and meet other clients’ needs and deadlines. The contractor could not stop boring once inside Zone A, so the dedication of CP&Y’s survey technicians continued into the weekends to provide reports to the Railroad Engineer and contractor on Saturdays and Sundays as well.

Snapshot of Railroad Bore Monitoring report spreadsheet.
Snapshot of Railroad Bore Monitoring report spreadsheet.
Train passing survey equipment.
Train passing survey equipment.

Safety & Excellence

Troy and Matt went above and beyond to provide survey services – rain or shine, weekday or weekend.


Train passing survey equipment. By prioritizing accurate equipment, utilizing tight control, and providing measurement reports frequently and regularly, Troy and Matt ensured the safety of our team, the entire construction site, railroad employees, and local area traffic.


Other safety efforts included meetings with the Railroad Inspector and Flagger every morning to review the day’s potential hazards and mitigation strategies. As with many of our projects, Troy and Matt’s mindfulness of traffic in the surrounding area also kept our team safe. Last but not least, CP&Y’s surveyors were equipped with our regulation PPE gear (steel toe shoes, safety glasses…etc.).


Another great effort on this project – keep up the good work, Troy and Matt!

Want to Know More?

For more information about our field services, like survey, contact Fabian Mendoza, CP&Y Field Practice Director, by email at fmendoza@cpyi.com or by phone at 214.640.1756.



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