Weldable tunnel steel sleepers are specifically designed for applications where high strength and permanent or semi-permanent fixation are required, such as supporting TBM gantries or heavy-duty logistics tracks. Unlike standard bolted versions, these sleepers feature components intended for direct welding to rail components or the tunnel's structural steel.
Types of Weldable Components
Forged Fixed Seats: These are often made from rolled steel selected for its weldability to the base sleeper. They allow for the use of elastic fastening systems like Pandrol clips by being fully penetration welded to the sleeper.
Weldable Rail Clips: These clips can be directly affixed to the steel surface of the sleeper to facilitate easier access and installation of rails during the construction phase.
U-Profile Reinforcements: Some modern designs include a welded U-profile underneath the sleeper trough to prevent it from jamming with ballast and to allow for easy replacement of hook bolts.
Common Profiles for Welding
H-Beam Sleepers: H-beam sleepers can eliminate cumbersome welding processes by using pre-welded base plates or being directly integrated into steel girder bridges.
Y-Shaped Sleepers: These consist of two curved I-shaped girders that are welded together via steel flanges at the top and bottom, providing exceptional frame rigidity and horizontal stability.
Benefits in TBM Projects
Load Distribution: Weldable connections ensure that high vibrations from TBM construction vehicles do not loosen critical track supports.
Custom Adaptability: For TBM gantries, sleepers are often processed using steel plates or channel steel that are bent and welded to match the specific diameter and curved invert of the tunnel.
Refurbishment: Existing steel sleepers can be refurbished by welding on new base-plated shoulders or joining multiple sleeper sections to extend their service life to approximately 50 years.
Signum Rail Fastening offers a wide range of sleepers for different purposes. Signum also offers customization based on your TBM's specific gantry distance and axle load requirements.
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