Rspctd mam urs way of explanation is vry nice, for this a lot of thnxx mam ,i m retired SSE from SE Railway, i was expert in flash butt welding field, bt i need u expert in pway field it is my dream,hnce urs rqstd to kindly help me in dis regards,i m 64 +yrs old student mam 😮😅😂