Enjoying my recently arrived Bing for Bassett Lowke "George the Fifth" O gauge clockwork loco. It's quite a nice runner- makes two full laps around my O gauge circuit on a single wind. The tender looks great with it, but it appears to be from another engine as both the engine and tender have "pins" instead of one having a slot to hook them together. My other question was, what is the middle spring-loaded lever? The outer push/pull rods are forward/reverse (reversing lever) and stop/go (brake lever). Shortly after posting this I found a scan of an instruction sheet on the internet so I have edited the post; the answer apparently is that it is the Setting Lever (aka "Restarting Lever") intended to work together with a special track section to permit the loco to not only stop via trackside setting, but also to restart once the trackside lever is released. After seeing the sheet I realized I have one of these track sections, so I'll give it a try.
Some photos and a brief video included below. The video includes one of my other clockwork pieces, an Orbor stationary power plant with bucket loader. Enjoy