This lockstation is where old meets new and where unusual is the norm. Here the modern, electric swing bridge is being closed after a boat had gone through an older style lock using the swing bar system. The first photo below shows the layout of the chains in this system which came into use in 1835 and was replaced in 1895 by the push bar system in use at most of the locks. The chains in a swing bar system are attached to an extension of the lock gate as opposed to being attached to a push bar which is then attached to the corners of the gates. An advantage of this system is it allows the gates to be operated in the event the chains are damaged since the swing bar could be pushed by people or horses. I'm not sure why this system was phased out in favor of the push bar system but it does appear to require a larger footprint. The locks here at Old Slys, named after old man Sly who was an early settler in the area, are one of only a few left that use the push bar system. An active railway bridge also crosses Old Slys Locks juxtaposing these two early methods of transportation, rail and water.