By the way the material for the piping / pipeline sections is API 5LX65, while that for the pig trap is A106B.
Tried the said scheme, but seems it didn’t work-out. Please let me know if my understanding is correct,,,, what I have done is changing back or re-instating the API 5L X65 material for the pipeline / piping component while keeping the A106B for the pig trap barrels. Still could not get rid of the overstress at the barred tee.