What Happens When You Reconstruct the Only Bridge in Town?
Like many Upper Midwest towns in the late 1800s, the
City of Lake Park, Minnesota, was founded along the railroad. Large and small, many towns throughout the region have the railroad to thank for their starts and early sustainment. They built businesses, homes, and roads around the tracks that were their lifelines. Even now, you can see old tracks running through downtown Lake Park, an offshoot of the mainline that was used by the town’s grain elevator.
Nowadays, train traffic has increased, roads are busier than ever, and the Upper Midwest has a more diverse economy. Given the chance to do it all over again, urban planners would probably propose a layout other than one where railroad tracks run right through the heart of a city. But the tracks are where they are, and cities have found ways to minimize the challenges of railroads while continuing to benefit from their presence.
A Town in Two Parts
In Lake Park, the railroad runs east and west, splitting the town roughly into two halves. The north part has a large portion of the population as well as a grocery store, bank, restaurant, and most of the commercial businesses. The south half includes a school, connects to US 10 (the main corridor through the region), and is home to its own significant portion of the population.
Residents and businesses in Lake Park depend on access between the two halves. Businesses receive traffic from US 10, and residents in the north attend school or commute along US 10 to jobs outside the community.
A bridge was constructed over the BNSF railroad decades ago to ensure that there would be unhindered access over the railroad at all times. This bridge has served motorists and pedestrians well while also allowing the railroad to continue business uninterrupted below. However, the Becker County Highway Department recently determined that the bridge had reached the end of its service life and the time had come to replace it.
Maintaining Access Over the Railroad
Replacing the bridge in Lake Park, while necessary, threatened to temporarily remove residents’ only means of crossing the tracks in town. This was deemed unacceptable. The next closest crossing is located about 1.5 miles west of town on a gravel road, which would have not only been inconvenient—adding miles to travel routes—but also less safe. The crossing west of town is at-grade and, considering a high-speed train is present every 45 minutes and the roadway’s average daily traffic would increase to up to 1,000 vehicles, the risk of a train-vehicle collision was determined unacceptable to Becker County and BNSF. This crossing also is on a gravel surfaced road, has limited advanced warning devices, and no intersection lighting.
The County retained HEI to serve as civil engineer for the project and come up with a solution to keep traffic flowing. HEI worked with the County to create a construction phasing plan that would preserve a grade-separated railroad crossing in town through the construction zone by using the existing bridge. A construction staging plan was developed that would allow the new bridge to be constructed one-half at a time. A single lane of traffic and a pedestrian path would be maintained throughout construction operations.
The previous timber structure was nearly 75 years old and had sustained several train impacts over the years as well as a recent vehicle impact. These issues, along with its age, created concerns over stability during demolition and temporary traffic use. The structure was analyzed to determine its stability before half of it was demolished. With new load ratings and other restrictions in place, traffic was reduced to a single lane over the timber structure (temporary signals at either end managed traffic flow). After the first stage of construction, traffic was shifted to the new adjacent half structure, and the remaining half of the initial structure’s demolition was completed. The rest of the new bridge was then constructed.
In the fall of 2018, construction for the bridge was successfully completed, and two-lane traffic, pedestrian passage, and access to the future multi-use trail were all restored over the new bridge. The new bridge serves the same basic purpose as the old—get people over the tracks—but it will do so with several improvements. Pedestrians will have a protected shared-use path, BNSF will have the option to add an additional track, and the stability of the structure itself will mean it can serve the city for several decades into the future.
Keeping the Public Informed
As added value to the client and residents of Lake Park, HEI created a
Facebook page for the project to post frequent updates on the construction progress including milestone moments and traffic impacts. HEI's drone team flew this area to capture footage of the project's progress from construction to completion to share powerful video and photo content.
The City of Lake Park shared these posts through their communication channels as well to help get the word out to residents to keep them informed throughout the project.
Client Benefits
- Provided a practical bridge design alternative that maximized budget and serviceability.
- Solicited and coordinated City of Lake Park project input.
- Provided improved roadway geometrics, desired railroad clearances, and adjacent site improvements.