The final phase of the Union Street Link was the construction of the north-south crossing under the existing George-Mossel Bay Railway line. The roads Rand St & Ring Rd on the southern side of railway line had to be re-aligned and re-graded to the future underpass level. A temporary rail link to the siding line enabled the two rail over road bridges to be constructed in phases – without interrupting the main rail line service. The main rail line had to be re-graded for some 600m to accommodate the underpass. A design constraint was to minimise the impact and access disruptions to the private properties adjacent to the road and rail re-alignments.