Indian cities are going vertical — and underground. With more than 15 cities either operating or building metro systems, metro rail construction has become one of the fastest-growing segments in Indian infrastructure. Here is how these massive projects actually get built.
Alignment Selection: Elevated vs Underground
The first engineering decision is the alignment. Elevated metro corridors using viaducts are cheaper and faster to build, ideal for wide arterial roads. Underground metro sections are used in dense city cores where surface space does not exist — but at 4–6 times the cost per kilometre. Most Indian metros use a hybrid: elevated for suburbs, underground for city centres.
Foundations and Pier Construction
Viaduct construction starts deep underground. Bored pile foundations — typically 1.0–1.5 m diameter, 20–30 m deep — transfer loads to competent strata. Pile caps and rectangular or circular piers rise above ground, built with reinforcing steel cages and high-grade concrete. Pier positioning must be precise to millimetre tolerances for girder launching.
Girder Launching and Viaduct Deck
Span segments (usually 25–32 m) are either pre-cast at casting yards and launched with gantry launchers, or cast in-situ using movable scaffolding systems. Once girders are placed, the deck slab is cast, prestressed where required, and waterproofed. A typical metro viaduct achieves 2–3 spans per week with mechanised launching.
Stations and Underground Sections
Metro stations are multi-level structures — concourse, platform and service levels — built with RCC frames, cladding and architectural finishes. Underground sections use cut-and-cover methods in narrow corridors or TBM tunnelling for long tunnels. Utility shifting (water, gas, sewer, telecom) is often the most time-consuming preliminary work in Indian cities.
Depots, Trackage and Systems
Every metro needs a depot: stabling lines, inspection bays, workshop buildings, and washing plants. Along the corridor, track laying, electrification (OHE), signalling, platform screen doors and telecom systems are integrated before trial runs begin. Civil contractors typically hand over the viaduct and station structures before system integrators take over.
How Kuberagroup Contributes
Kuberagroup executes metro civil packages — viaducts, station structures and depot works — with modern launching equipment and safety-first protocols for dense urban sites. Read more on our metro rail services page or get in touch to partner with us.
Frequently Asked Questions
What is the difference between elevated and underground metro?
Elevated metro uses viaduct structures above ground — cheaper and faster to build — while underground metro uses tunnels below ground, ideal for dense city centres but significantly more expensive.
How are metro viaducts built?
Metro viaducts are built on bored pile foundations with RCC piers, followed by pre-cast or in-situ girder launching and deck slab construction using gantries or movable scaffolding systems.
How long does metro construction take in India?
A typical elevated metro corridor of 15–20 km can take 3–5 years from kickoff to commissioning, including utility shifting, civil works, systems integration and trial runs.