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Specialized Engineered Products (SEP Group) at work:

The Traveler

Here is the traveler - 126 feet long, spanning from one side of the platform to the other side. It is a product of SEP which build elevators and travelers that perform with a bit of magic - as in going around curves and going uphill and downhill without sliding.

The traveler is a sort of horizontal elevator that moves along the inner edges of the edge girders. It is used for cleaning, inspections and maintenance. This traveler moves at a maximum rate of 60 feet/min but the usual rate is 15 feet/min. But perhaps the more interesting part of the traveler is how it maintains its perpendicular alignment with the edge girders. For example, if the left side travels a bit faster than the rights side, then the overall traveler is skewed. Think about it - how would you design the controls to maintain a minimal skew?

The north end of the traveler. The drive assembly rides on the lip of the lower "I" of the outside edge girders.

The middle of the traveler

The south end of the traveler

According to Murray, "our" Cooper River Bridge traveler is the longest single unit traveler in the world. It was shipped in three pieces and then spliced together. It is powered by 480 volt AC motors and controlled by a computer system. Murray smiles and declares that he has the most powerful remote control in the world and can travel the full distance of the main and back spans with his remote control.

Here is Murray, and the southern end of the traveler with a motor and gear/wheel drive on the left and on the right (gray boxes).

Here you can see the top of the traveler (black region) and the underside of the bridge

Here is a view of the drive motor and the lower lip of the north edge of the bridge

And here is wheel assembly as it rests on the inside and outside edge girder lips. Note that the roller uses about 4 inches of the bottom of the edge girder as a track. In the background you can see the bearning that buffers the movement of the bridge deck relative to the inner pylon face.

Here is the traveler control box and a view of the computer that is mostly is chilling out inside

The remote control - how to "call" the traveler when it is stationed at the east pylon and you are waiting on the west pylon.


There are four elevators, one for each inner face of each pylon. The elevators are interesting because not only do they travel up and down following the incline guide rails, but at the level of the pylon crossbeam, the incline reverses.

The channel that wraps around the cab has a pin supporting the cab and permits the elevator cab to maintain vertical alignment similar to a ship's compass.

Here, the elevator is at the lower level (basically a 3 stop elevator: pylon crossbeam / traveler level, the main deck and the top.

Here is the view of the bottom of the pylon shaft - looking up from the base of the pylon. The box is the elevator shaft passing through the pylon cross member.

A view of the elevator coming up

Here the elevator as it approaches the main deck level.

There is a lower level near the base of the pylons - looking east and west from almost the base of the east pylon

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Attribution: C. Frank Starmer from