Infinity Loop Rail Design

Infinity Loop rendering

Infinity Loop Rail Design

A Better Freight Rail Facility

Train loading and unloading has remained virtually unchanged in North America since the 1960s. At origin and destination facilities, balloon loop tracks are used to load and unload products transported by train. While the present unit-train loop tracks can arrive, depart, or process a single unit train at a time, they cannot efficiently process multiple trains at a high rate. The throat area — where trains enter and exit — clogs because trains arriving, departing or being processed cross the same tracks. The only solution has been to increase the facility size — until now. Our railway engineers were determined to find a better way. 

HDR freight rail engineers put their decades of experience to work and designed the ingenious, patent-pending Infinity Loop. A revolutionary idea, the invention solves the decades-old capacity limitation and allows facilities to process multiple unit trains at the same time without impacting mainline traffic. Bottlenecks that had the potential to send delays rippling through rail network are eliminated. The reduced delays and increased throughput have the potential to radically increase efficiency and could eventually impact commodity prices. 

Layout of the Future

How does it work? Our team wrapped a staging yard around a standard balloon loop track. By wrapping the staging tracks — each capable of holding a unit train — around the balloon, the footprint was minimized and the layout resembled an infinity symbol, inspiring the design name. The combined staging tracks and interior balloon form an endless design that allows multiple tracks to enter their facility without conflicting with other unit trains loading and unloading. Trains on the loop are also turned around during the loading and unloading process, avoiding the need to stop and move locomotives from one end of the train to the other, as required in conventional designs.

The new design allows rail facilities to operate more densely, minimizing property acquisition costs and using previously unused space. To accommodate multiple trains, current track designs must greatly expand their size, requiring additional real estate, maintenance and site work. In the Infinity Loop, however, the number of staging tracks is essentially unlimited with minimal operational impacts and increased costs. 

Besides improving efficiency, the design eliminates train car shunting and engine revving, significantly reducing noise pollution and general nuisance to neighbors. And the design allows easier access to land inside the center of the loop, making it available for storage of commodities or cargo.

Adaptable to Many Needs

The Infinity Loop works for multiple facility types, including bulk material, intermodal and liquid-bulk. In each case, the design leads to smaller space requirements, more efficiency and fewer pinch points. For liquid-bulk trains, for example, the Infinity Loop can process two full-length trains simultaneously or a single train split on adjacent tracks twice as fast. 

The interior tracks can also serve different freight companies, who can share staging tracks without conflicting with each other. The track-sharing could be a considerable plus for budget-conscious companies exporting or importing materials.

The new design also opens new possibilities for facility locations. Historically, shipping and receiving facilities had to be located near mainline tracks and unencumbered by grade crossings. The new design allows them to be located anywhere, and their shape does not require specific land configurations or grade separations.

More flexible, easily scalable, using less space; the Infinity Loop has the potential to radically remake the future of freight rail facilities.

Infinity Loop rendering



Grand Award (2019)
Engineering Excellence Awards
American Council of Engineering Companies
Honor Award (2019)
Engineering Excellence Awards
American Council of Engineering Companies of Oregon