How Seamless Long Rails Are Made and Laid
The welding of long rails is carried out on flash butt welding machines at the rail welding plant. The complete process includes rail matching (matching rail ends by profile), straightening, rail-end treatment, welding, removal of weld flash, normalizing, grinding, straightening and ultrasonic flaw detection. The welded long rails are loaded onto special rail transport trains and delivered directly to the track-laying site, where they are unloaded on both sides of the track from the guide chutes of the last rail car. On site, the long rails are welded to the specified design length by aluminum thermite welding, and the old standard rails are replaced within the specified track-laying temperature range.
The Rail Replacement Operation
Rail replacement is carried out by two rail-replacement trolleys pulled by rail cars, about 20 meters apart. The first trolley lifts the new rail and removes the old rail, placing the new rail on the concrete-sleeper support platform; the second trolley lifts the old rail and feeds it into the track center. In this way, the new and old rails are continuously exchanged in a horizontal figure-8 pattern as the trolleys move forward.
Maintenance Rules for Seamless Lines
1. Rail Temperature Discipline
Seamless lines must be maintained according to rail temperature: it is strictly forbidden to carry out any maintenance work when the rail temperature deviates more than ±20 °C from the locked rail temperature.
Work that relieves or adds rail stress (such as rail replacement, loosening fastenings over long lengths) must be planned within the permissible temperature window.
Record the rail temperature at the time of work and re-verify the locked temperature after the work is complete.
2. Protection of Ballast Resistance
During maintenance, ensure that the resistance of the ballast bed is not damaged, or is damaged as little as possible. Ballast shoulder, crib and sleeper-end conditions determine the line's resistance to longitudinal and lateral movement; disturbing them without restoring is a common cause of track buckling.
3. Operational Planning
According to the characteristics of the seamless line, arrange the operation plan and sequence reasonably to ensure line stability: minimize the length of simultaneously loosened fastenings, work from the ends of stressed zones toward the middle where required, and re-tighten and stabilize before traffic resumes.
Broken Rails and Expanded Rails
Broken rails and expanded (buckled) rails of the seamless line pose a great threat to driving safety:
- Prevention: regular ultrasonic flaw detection, rail-gap and alignment monitoring, ballast consolidation, and strict compliance with the temperature window are the primary preventive measures.
- Broken-rail handling: stop traffic immediately, protect the site, measure the gap and rail temperature, and repair with a low-temperature joint bar or thermite weld under qualified supervision; restore the locked stress condition afterwards.
- Expanded-rail handling: release the excessive compressive force in a controlled sequence (loosen fastenings in stages, adjust gaps at joints), never cut the rail without re-locking planning, and restore the ballast before reopening.
Seamless-rail maintenance is governed by three disciplines: respect the locked rail temperature, protect ballast resistance, and plan operations so the line's stress state remains stable. Applied consistently, these rules keep continuous welded rail safe and long-lived.
Request Rail Specifications & Pricing
Regular maintenance of seamless rails is essential for controlling rail stress, alignment, wear, and surface defects. Proper inspection and timely maintenance help maintain track safety and extend rail service life. GNEE RAILWAY RAILWAYL supplies steel rails and related fastening components for different railway track requirements.
