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Nuttall Gear Custom Gear Drives for Vertical Lift Rail Bridge
In July of 2018, the Union Pacific Railroad replaced its aging 614 ft. long swing
bridge over the San Bernard River near Angleton, Texas. The new bridge is a vertical
lift design with a 114 ft. long center span that raises 56 ft. above the Mean High
Water (MHW) level to allow marine river traffic to pass under. The busy bridge carries
19 trains per day (both commuter and freight).
To diminish track outage time, engineers designed the new bridge’s center vertical
lift span to be fully constructed alongside the existing bridge and slid into position
quickly once the old bridge’s center swing section was removed. This radical approach
to bridge construction had never been attempted before. The entire center section
replacement process took only 80 hours to successfully complete.
Nuttall Gear worked with the bridge engineering team to design and manufacture the
primary differential reducer and 4 secondary reducers required for the new vertical lift
bridge. All the enclosed drives featured fabricated steel housings, and all welds were
inspected by an Independent Certified Weld Inspector (CWI). The project had a US
origin steel requirement.
- Primary Parallel Shaft Differential Reducer:
Input rating: 20 HP @ 1170 RPM, Reduction ratio: 20.84:1
- Secondary Parallel Shaft Reducers:
Input rating: 5 HP @ 56 RPM, Reduction ratio: 78.5:1
Highlights
- Custom-designed enclosed
reducers
- Fabricated steel housings
- Special center distances
- Load tested to 150%