Bolt, bogie pt no C-86015

[brit plumber]

I’ve noticed I’ve got 2 versions of the Bogie bolt pt. no. C-86015. Is it a case of different manufacturers or perhaps a early v late difference?

The one on the top is shown in Ord 9 TM9-710 page 254. It has little slots cut out of the top edge. The 2 on the bottom don’t have the slots because the bar is actually lower in relation to the threaded ends.

[ph5200]

I have two tracks and am taking parts from one to finish the other.  I noticed the same thing.  One of my manuals states, To provide for the additional weight of guns and other heavy equipment, a heavier volute spring No 3 is now being used.  The new No 3 spring compresses to 9 1/4 inches under a load of 5000 pounds compared to 8 inches for the No 1 spring.  Installation of the new spring requires machining of the bogie arm tie bolt surface to provide more operating clearance between it and the crab assembly.  I think this is what you are referring to in the picture, don't know if there were any updates.