A transmission tower or power tower is a tall structure, typically a steel lattice tower, which is employed to support an overhead power line. Economic losses will be the consequence of any transmission line system failure that disrupts the energy supply. This article describes the MD (300-600 Dev./D.E.-00) NT +9M body extension redesign and structural analysis for a 220 kV multi-circuit transmission tower. This paper pertains to the failure transmission tower structure and implementation of the failure structure through the use of CAD, ANSYS, and analytical and experimental testing. Experimental testing in 2018 resulted in the failure of this MD type transmission tower. The research conducted in this paper is the first to analyse and track the progression of failure of a segment of a transmission structure, in contrast to previous studies that have examined the behaviour and failure of a single tower. To accomplish this, a distinctive CAD/numerical model is developed in this paper. This article will provide a comprehensive discussion of the formulation and validation of the various components of this CAD/numerical model, which are reported in various sections of paper. This study helps build transmission towers to handle rising voltage and power demands in electrical networks.