At their deepest point, the tunnels will be around 60m below ground, the equivalent depth of a 16-storey building. On average, the SRL East tunnels will be approximately 26m deep – that’s about 6 storeys below ground.

Building tunnels deep underground helps avoid existing infrastructure, utilities and building foundations. It also reduces disruption to homes, businesses and roads above ground, allowing construction to continue safely with minimal impact on daily life.