Over the period of time, there has been a growing utilization of natural resources in civil engineering construction. The extraction and utilization of crushed stone impact both the environment and the economy of a nation. In this context, the present study examined the use of steel slag ballast (SSB) as a replacement for conventional granite ballast (GB), aiming to reduce burden on natural aggregates. Large scale direct shear tests were conducted at normal stress (σn) of 50, 100, and 150 kPa and at shearing rate (Sr) of 6 mm/min for slag-granite ballast mixture. Further, cyclic triaxial tests were conducted using track simulation testing (TST) apparatus at loading frequency (f) of 20 Hz. Direct shear test results indicated that as the proportion of SSB in GB increased, both the peak value of shear stress (τ) and the corresponding friction angle (φ) increased. Furthermore, cyclic test results signify that the SSB exhibited higher value of resilient modulus (Mr) but with substantially lower breakage (Bg) compared to that of GB. In addition, cyclic test results also demonstrated that Mr decreases with increase in Bg of slag-granite ballast mixture. Moreover, τ and Mr of SSB80 (80%SSB-20%GB) was found to be almost similar to 100% SSB. In this context, SSB80 may be considered as an optimum content of SSB to be mixed with GB.