... do with the single slip actuation? does anyone have a clearer picture of this type of mechanism? When I look at the slip rodding what I think I see is the rod locating in the crank before you get to this mechanism and a rectangular bar of sorts connecting from the main rodding run to the crank in front of this- so on the face of it it seems that it is not part of the actuation? Tim edit... attached is the signal diagram and the picture from which the detail is taken.2999_280729_430000000.jpg 2999_280730_090000000.jpg Last edited on 28 Nov 2017 17:28 by Tim Lee posted: 28 Nov 2017 17:42 from: Martin Wynne Hi Tim, If it's not a compensator, it is very difficult to imagine what else it might be. There were lots of patent designs for compensators and suchlike, here's a typical vertical compensator: 2_281237_240000000.png If it is a compensator, it will be roughly half-way between the signal box and the points (assuming no compensation is being done by cross-rods and cranks). The ...