In present days the use of large diameter long “RCC Bored Cast-in-situ Pile Foundation” is becoming popular for supporting the long span bridge like the “Railway-Over-Bridge (ROB)” structure crossing over multiple railway lines. The groups of 1500 mm diameter and 45 m long “RCC Bored Pile Foundation” were used to support two high “Pylons” carrying the cable-stayed central main span of 100 m length crossing over seven railway tracks along with the adjoining span of 60.00 m in one side and another span of 47.50 m on other side of the newly constructed ROB. The said ROB structure is located adjacent to the “Majerhat Railway Station” at chainage of 5.80 km on Diamond Harbour Road (NH-117) in Kolkata, West Bengal. Initially the detailed geotechnical exploration works comprising of field investigations by drilling deep borehole and laboratory tests were undertaken for the foundation soil layer profiles at every “Pylons” and other adjoining substructures locations. By using the geotechnical investigation data, the design estimation of vertical load carrying capacity of single 1500 mm large diameter and 45 m long bored pile shaft in soil was done as per the relevant BIS and IRC guidelines. The confirmation of theoretically estimated vertical load carrying capacity of “RCC Bored Pile Shaft” which was an essential and integral part of “Geotechnical Design of Pile Foundation” was done by conducting the “Bi-directional Static Pile Load Test (Compression)” corresponding to the “Initial Load Test” over the “Test Pile” other than “Working Pile” following the relevant ASTM and IRC guidelines. After few months of time gap, the same “Test Pile” was also tested for verifying its load carrying capacity including the shaft integrity through “High Strain Dynamic Vertical Load Test” as per the available ASTM and IRC guidelines. The load–deflection behavior of the “Test Pile” obtained from the “Dynamic Test” was compared to the results of “Static Test” and the correlation in between the two types of vertical load tests was established. Later the “Dynamic Vertical Load Test” was adopted for confirmation of the required “Safe Design Load Carrying Capacity of Single Working Pile” under “Routine Load Test”. This paper presents the above said project case study of “Majerhat ROB” structure covering the theoretical estimation of vertical load carrying capacity at initial stage and then its field verification through “Static” as well as “Dynamic” tests for the large diameter long “RCC Bored Pile Foundation” in soil.