Hirail

Hi-rail, also written hy-rail, refers to a road-rail vehicle designed to operate on both highways and railroad tracks. These dual-mode machines are used primarily for maintenance of way (MOW), inspections, and light construction tasks, enabling crews to move quickly between work sites and to perform track-side work without separate locomotives or cranes. Hi-rail vehicles are common in North America and in other regions with extensive on-track maintenance needs.

Design and operation

Hi-rail vehicles are typically built on a road-going chassis with retractable rail-wheel assemblies that enable travel on rails. When workers need to operate on the track, the rail wheels are folded down or engaged, allowing the vehicle to move along the rails under rail operations rules. Most units have an operator cab, road tires for highway use, and hydraulic or mechanical systems to switch between modes. A wide range of attachments can be fitted, including booms, cranes, loaders, buckets, plows, or tamping and ballast equipment, depending on the job. The speed and capabilities of a hi-rail unit depend on its design and the track conditions.

Uses and operations

Hi-rail vehicles support routine track inspections, vegetation control, signaling and cable work, and lightweight repair tasks. They are employed by railroads and contractors to reach remote or dangerous areas, deliver tools and equipment, and perform on-track maintenance without requiring a dedicated locomotive or a separate maintenance train. Operations follow track protection procedures and require coordination with railroad dispatchers and on-site safety protocols.

Safety and regulation

Operations are regulated by national and regional railway safety authorities. Operators require specialized training and certifications, with strict adherence to on-track safety rules, speed limits, and clearance requirements. Regular maintenance of the dual-mode wheels, braking systems, and attachment interfaces is essential to safe operation.