It looks like 160.A.1 was fitted with Lentz(?) oscillating cam poppet valves, hence the two valve bores per cylinder.
One needs to look closer as they are black and in the background.
Did you notice the lengths of steel bar welded to the frames in front of, and behind, the cylinders to stop them moving?
If that was the case, one must wonder as to how Chapelon was able to modify these locos in the first place. It should be remembered that 242A1...
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