Technology Digests / Alternative Open Deck Bridge Ties and Hardware Update

TD26-020

Date Posted: September 15, 2026
Authors
  • Chris Johnson
  • Duane Otter
  • Dante DeVencenty
Share

Key Findings

  • Alternative open deck bridge ties tested at FAST performed well under HAL traffic.
  • Uniform-height glued-laminated (glulam) ties performed well at FAST for over 1,722 MGT.
  • Fiber-reinforced foamed urethane (FFU) ties performed well at FAST for over 1,542 MGT.
  • Tapered glulam ties have accumulated 929 MGT in a 5-degree curve and continue to perform well.
  • The glulam and the FFU ties showed no signs of warp, twist, major splitting, bowing, or crowning.
  • Between-the-tie hook bolts have required little attention for 742 MGT when installed in a tangent riveted top span.
  • Between-the-tie hook bolts have shown no lateral movement in over 929 MGT in undapped ties on a smooth top span located in a five-degree curve.

Alternative Open Deck Bridge Ties and Hardware Update

MxV Rail has been testing open deck bridge materials as part of the Association of American Railroads’ (AAR) Strategic Research Initiatives (SRI) program. Since 2009, alternative material bridge ties intended to perform better and last longer than traditional timber ties have been evaluated for long-term performance under heavy axle load (HAL) traffic at the Facility for Accelerated Service Testing (FAST®)* in Pueblo, CO. Deck hold-down fasteners that require less effort to install have also been evaluated as part of this ongoing test. This Technology Digest provides an update on this testing. BACKGROUND Many steel railroad bridges in North America utilize an open deck consisting of timber crossties that support the rail above the structural steel. Often serving as structural members spanning the space between two girders, these ties are generally solid-sawn timbers that are both larger and longer than typical track ties. Hook bolts installed in holes in the ties…