ROB and RUB Construction – Utility Shifting Survey Guide

Updated: 23 October 2026

What is ROB construction and why does it replace level crossings?

ROB construction means building a road over bridge that carries a road above a railway line, so vehicles no longer wait at a gate. Its partner, RUB construction, takes the road under the track through a road under bridge or subway. Both are forms of level crossing replacement, and both remove one of the most common points of conflict between trains and road users.

Governments have pushed this work for years. The Setu Bharatam programme, launched on 4 March 2016, set out to make national highways free of level crossings, with 208 rail over and under bridges planned for that purpose. State roads and city crossings follow similar logic under railway and state cost-sharing arrangements.

Every one of these structures lands on ground that has been a busy road for decades, which is why buried services become the first obstacle.

How do ROB and RUB construction actually work?

Road over bridge

An ROB has a span over the tracks and two approaches that climb up to it. The span over the railway is designed and built to the railway's approval, while the approaches are usually the road agency's responsibility. Foundations are often bored piles with pile caps, followed by piers, girders and a deck. Approaches may sit on earth embankments held by retaining walls or on a series of smaller spans.

Road under bridge

An RUB is commonly built by pushing precast RCC box segments under the track. The track is supported on temporary girders, trains run at restricted speed, and jacks force the boxes through the embankment from a thrust bed beside it. Where conditions allow, a cut-and-cover method is used during a longer traffic block instead.

Limited height subway

Where only light vehicles need to pass, a smaller box gives a low-headroom underpass. It follows the same pushing or cut-and-cover principles at a lower cost.

Whichever type is chosen, the foundations, thrust bed, approach excavation and drainage all need ground that is free of services.

Which utilities get in the way of a level crossing replacement?

A road that has crossed the railway for a long time collects services on both sides. Typical finds include:

• Water and sewerage – distribution mains, rising mains and gravity sewers, often deep and hard to divert.
• Storm drains – roadside drains and culverts under the approach.
• Electricity – HT and LT underground cables, street lighting feeds and sometimes overhead lines that must go underground to clear the new structure.
• Telecom – optical fibre ducts from several operators.
• Gas – city gas distribution pipelines in many towns.
• Railway services – gate circuits, signal and telecom cables and earthing near the track.

Each belongs to a different owner, and each owner shifts its asset under its own approvals and timelines.

Which terms come up in ROB and RUB utility shifting?

• GAD – general arrangement drawing showing the structure, spans and approaches, approved by the railway for the portion over or under its track.
• Footprint – the ground taken by piles, pile caps, piers, retaining walls and thrust beds, which must be clear of services.
• Utility shifting – moving a service to a new alignment, at the project's cost, so construction can proceed.
• Deposit work – shifting carried out by the utility owner after the project deposits an estimate.
• Thrust bed – the reaction platform from which jacks push the RCC boxes.
• Diversion road – a temporary road that carries traffic during construction and may itself need a utility check.

How should utility shifting be planned for a bridge?

1. List likely owners. Municipal body, water board, DISCOM, telecom operators, gas distributor and the railway's own departments.
2. Collect records. Ask each owner for drawings, while accepting that many will be incomplete.
3. Survey the ground. Trace actual positions across the full footprint, approaches, drains and diversion roads.
4. Prepare a shifting plan. Show each service, its proposed new alignment and the order of work.
5. Obtain estimates and approvals. Owners usually price and approve their own shifting.
6. Sequence construction around shifting. Start foundations only where services have actually been moved.

Delays usually come from services discovered late, when a pile rig hits something nobody listed. Each surprise restarts the cycle of owner identification, estimate and approval.

Land ownership adds another layer. The part of the site inside the railway boundary follows railway procedures, while the approaches usually sit on municipal, state or highway land with their own permits. A single survey covering both sides gives every authority the same picture, so arguments over whose drawing is right are settled by field evidence rather than by correspondence.

Why does ROB construction need a GPR survey first?

Ground penetrating radar (GPR) sends a radar signal into the road and records reflections from pipes, cables and ducts below. An electromagnetic cable locator traces metallic lines along the approach. Together they show what the owners' records missed, before the contractor commits to pile positions.

For a bridge project, the survey is most valuable on:

• pile and pier positions on both approaches;
• the line of any pushed box, where a hidden pipe could stall jacking under live track;
• retaining wall and drain alignments along the ramps;
• temporary diversion roads that will carry traffic for months;
• the strip near the gate where railway cables meet civic services.

Penetration depth depends on soil and moisture, so very deep sewers may need trial pits as well. Our road and highway GPR survey covers approach roads, and the railway GPR survey covers the track-side strip. Mezux is not affiliated with Indian Railways or any railway PSU; our client is the contractor or owner who places the survey order. Any scanning inside railway land waits for the railway's permission, with blocks and safety staff arranged through the client.

What records help after shifting is complete?

Once services move, their new routes become the next generation of buried records. Keep:

• the pre-construction survey drawing showing every service found in the footprint;
• as-built routes of each shifted service, with owner names;
• depth notes at crossings under the new approaches;
• locations of abandoned lines left in the ground.

The railway's own view of crossings and track-side services is explained on our railways sector page, and digitised plans can be prepared through CAD and GIS utility mapping, quoted separately.

Planning a crossing replacement? Share the GAD or a sketch of the footprint through the quote form. Our route survey is ₹24 a metre plus GST, and an L-section adding a depth profile of detected services costs ₹32 a metre; the price list explains minimums and slabs.