Maybe some members already knew or explained before but I missed it and a quick search shows no concrete answer.
If I look at WT references for example, it goes from 51xx (5110->5130) to 5230 and 5131 to 5231. Then why did the 5296 went away but the 5196s stayed, like reversing trend?
Was it because of the movement? I thought 5296 using 324s is more modern than the 5196’s 215?
The new Calatrava 5212 also starts with 52.
Any good inputs, please?