GPR Survey for Railways – Signalling, OFC and OHE Works

Rates and page checked: 23 October 2026

What does a GPR survey for railways cover?

A GPR survey for railways checks the ground beside, under and across the track before a cable trench, foundation pit or bore is opened. Railway land holds far more buried services than its open look suggests. Old signalling cables, telecom quad cables, optical fibre, earthing strips, drains and municipal pipes can all lie within a few metres of the rails.

These lines went in decades apart, laid by different departments, and the records rarely agree with each other. A railway utility survey closes that gap. Ground penetrating radar (GPR) sends a radar signal into the ground and records echoes from cables, ducts and pipes, metallic or plastic. Where a line carries metal, such as a power or signalling cable, an EM cable locator traces it as well.

The outcome is a marked corridor and a report telling the contractor what already sits there and roughly how deep. Typical railway scopes are:

• signalling and telecom cable trenches along the track;
• optical fibre routes and tower sites for Kavach;
• pit positions for OHE mast foundations;
• utility shifting ahead of ROB and RUB construction;
• cable and pipe crossings under the track;
• station redevelopment sites and circulating areas.

Which railway works need a buried-service check first?

Signalling and telecom cable trenches

New interlocking, block working upgrades and automatic signalling all need cable runs beside the track. A railway signalling cable survey shows where the existing cables lie, so a fresh trench does not cut a working circuit. One damaged signalling cable can halt trains on a section, which makes this the most sensitive scope on railway land. Our guide to railway signalling cable laying explains the cable side in more depth.

Kavach fibre routes and tower sites

Kavach, the automatic train protection system developed through RDSO, depends on optical fibre and radio towers along the section. A Kavach OFC route survey checks the planned duct line for clashes with older cables, culverts and drains, and checks each proposed tower spot for buried lines. Background on the system is in our Kavach and OFC article, and our OFC route GPR survey service describes clearing a duct line from end to end.

OHE mast foundations

Overhead equipment masts stand on foundations dug or augered close to the track at regular intervals. An OHE foundation utility check scans each pit position before the auger goes in, because a mast location is often exactly where an old cable runs.

ROB, RUB and utility shifting

Road over bridges and road under bridges need pipes, cables and ducts moved aside. A survey lists what must shift and where a diversion can run.

Crossings under the track

Cables and pipes usually cross the railway by HDD or by pushing a casing pipe under the formation. Our HDD route survey scans the planned bore line plus the launch and reception pits on each side.

Station redevelopment

Forecourts, parking areas and platform extensions mix railway services with city water, sewer and power lines. These are scanned as area grids rather than strips.

Track bed and ballast

Radar can also look at ballast thickness, fouling and the formation under the sleepers. That is a specialised scope with different antennas and processing. We quote it on request after discussing the objective; it is not part of a standard cable route survey.

Who orders a railway utility survey from Mezux?

Survey orders on railway jobs come from whoever is about to dig. In practice that means:

• signalling and telecom contractors executing work orders on a railway section;
• sub-contractors to EPC companies on new lines, doubling, electrification or Kavach packages, including packages let by organisations such as RVNL or IRCON;
• telecom operators and infrastructure providers laying fibre on railway land under a way-leave;
• civil contractors building ROBs, RUBs, foot overbridges and station buildings;
• power distribution companies and their contractors taking HT or LT cables across the track, a scope covered on our power utilities page.

We have no affiliation with Indian Railways or with any railway PSU. Our client is whichever contractor or owner signs the order, and the findings are handed to that client.

Fibre work beside the track is close to our everyday telecom jobs. The telecom operators page shows how fibre routes are cleared, and the same methods carry over to optical fibre laid within the railway right of way.

How do traffic blocks, safety and way-leave shape the work?

Railway land is not an ordinary roadside. Nobody goes near a running line without the railway's permission, and our crews follow that rule without exception.

• Permission and way-leave: the client secures access to railway land and, for fibre or utility lines, the way-leave or licence for the route.
• Blocks: scanning within the track zone, or across it, happens only inside a traffic or power block granted by the railway. The client books the block.
• Supervision: where the railway requires a supervisor, lookout or escort, the client or the railway provides one.
• Our part: crews arrive briefed with equipment already checked, so block minutes go into scanning rather than setting up. They work under our ISO 45001:2018 safety system.

Strips well away from the running line, such as a cable route near the boundary fence, can often be scanned by day without a block, subject to the railway's rules on that section. Sorting out which lengths need a block and which do not is part of scoping.

What does the contractor receive, and how is it billed?

At the end of the job the services are painted or pegged on the ground, and a report records each one: where it runs, roughly how deep, what it probably is and whether radar, EM or both picked it up. How far the radar sees depends on the soil. Damp clay and salty ground shorten penetration depth; dry, sandy soil extends it. So the report gives the achieved reach for each length of the route and flags any patch the crew could not get onto.

Pricing on railway work follows the same published card as any other route:

• ₹24 a metre for the plain GPR scan, or ₹32 a metre when an L-section is ordered so that a depth profile of the services found runs along the whole alignment;
• no order billed under 4 km, and for sites beyond Delhi NCR no project billed under ₹1,00,000;
• volume relief on the entire order once it passes 100 km (25% less), 500 km (40% less) or 1,000 km (half price);
• GST added on the invoice.

Some items sit outside the metre rate and show up as their own quote lines: getting crews and systems to site, shifts worked after dark, traffic management or permits, and CAD or GIS drawing sets. Where a depth must be proved, trial pits or boreholes can be ordered too.

How do you start a railway survey with us?

Send the section name, the chainages or a KML of the route, the work type (signalling, Kavach, OHE, crossing or station) and the block windows you expect. We reply with a scan plan and a quote. For a track-side cable job, the railway GPR survey page sets out the method stage by stage, and the form below reaches our Faridabad office directly.