Van Buren, AR - Arkansas River Bridge

Discussion in 'Bridges' started by railroadguy65, Mar 8, 2009.

  1. Turky44

    Turky44 Member

    So looking at condren rails and here, it seems at one point there was a turn span of the bridge?

    looks like turning mechanism is still there
  2. klrwhizkid

    klrwhizkid Administrator Staff Member Administrator Supporter

    Yes, but no longer needed to turn.
  3. No caboose.
    No trailer locomotive.
    Where is the phinally?
    Where is the pic of the photographer Turky44?
    ha ha
    Great vids!
  4. Joe Lovett likes this.
  5. Swing bridge turning systems can get complicated for the heaviest.
    The below clears up some thoughts about a swing-bridge span that is on a central pivoting pier.

    Centre bearing swing bridge general concepts:
    - In this type, span of the bridge is totally dependent on central pivoting pier.
    - To prevent the bridge span from failure under unbalanced loads i.e. wind loads, etc. balance wheels are provided which rolls on a large-diameter circular track concentric with the pivot bearing (at the center pier).
    - The design is based on the fact that the centre bearing supports all of the dead load when the span is in its open position. Some centre bearing designs are called king-pin bearing systems.
    - The live load is usually supported by centre and end lift devices which are actuated when the span is returned to the closed position.
    - Rotation of the span is provided by machines which are normally operated manually. It normally has a motor with a speed reducing system. That turns a vertical driving-drive-shaft which in turn operates the input to a gear-train mechanism which reduces each successive shaft's turning speed.
    - The gear-train mechanism final gear turns the vertical driven-drive-shaft that has a lower output gear which walks-about the large cog-gear on the top of the central pivoting pier.

    Normally, the large-diameter circular track's outside surface is the large machined cog-gear mounted on top of the central pivoting pier. The large-diameter circular track is normally flat. The balance wheels may be replaced by rollers. Rollers can be used when loads are much higher. Designs using rollers normally have a large-diameter circular over-head track and a below track (the roller is loaded both overhead and from below). The rollers can be tapered and matching sloped flat tracks in order that the forward speeds across the entire roller are the same. When balance wheels are chosen, they are narrower and are loaded on their bottom and at the wheel's axial.
    Last edited: Aug 10, 2020
    Ozarktraveler, Turky44 and Joe Lovett like this.
  6. (c) Across the Arkansas Waterway, the draw of the Van Buren Railroad Drawbridge, mile 300.8 at Van Buren, Arkansas,
    is maintained in the open position except as follows:

    (1) When a train approaches the bridge, amber lights attached to the bridge begin to flash and an audible signal on the bridge sounds. At the end of 10 minutes, the amber light continues to flash; however, the audible signal stops and the draw lowers and locks if the photoelectric boat detection system detects no obstruction under the span. If there is an obstruction, the draw opens to its full height until the obstruction is cleared.

    (2) After the train clears the bridge, the draw opens to its full height, the amber flashing light stops, and the mid channel lights change from red to green, indicating the navigation channel is open for the passage of vessels.

    [CGD08-06-005, 71 FR 70879, Dec. 7, 2006, as amended by USCG-2007-0043, 73 FR 24868, May 6, 2008; USCG-2010-0441, 75 FR 65232, Oct. 22, 2010; USCG-2010-0228, 75 FR 66308, Oct. 28, 2010]
    Ozarktraveler and Turky44 like this.
  7. john

    john Supporter

    History of the Fort Smith bridge in two drawings. From a presentation I did last year. VB Bridge.jpg
  8. john

    john Supporter

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