NNG Early Switch Stands, Broad gauge

In doing research on the Weldon & Petersburg RR (5 foot gauge in Virginia), at the end of the Civil War, we found this image of the RR shops and roundhouse. As expected, the switches are stub type. The area to the left is on fill and the switch stands are on long ties or bridge timbers to avoid more fill. Instead of "harp" linear movement type stands, these appear to be rotary type with a lever that turns a central shaft with, I assume, a crank at the base.

I inserted an enlarged portion showing the stands.



I had no idea this type was around in 1865. Anyone have more information on the use of this type switch stand in the early days?