Metro Station Utility Survey for Diversion Design

Why is a metro station utility survey the first site activity?

Because a station is the most utility-dense part of any metro or rapid-rail corridor, and nothing structural starts until its services are known and moved. Elevated stations sit on foundations in the median or kerb line; underground stations need a box spanning the road. Either way the footprint lands on decades of underground utilities.

Under a busy arterial junction in a big Indian city lie water mains, sewers, storm drains and 11 kV and 33 kV cables. Street-lighting cables, several telecom ducts and, increasingly, city gas lines join them. Different agencies laid them at different times. Some exist only in paper utility records, and a few on no record at all. The survey brings them onto one drawing before the station layout is frozen.

Which parts of the station need scanning?

More than the station box alone. We agree the survey limits with the design consultant as zones:

• Station footprint: the box or pier foundations, plus a working buffer.
• Diaphragm wall or secant pile line: scanned at closer spacing, because a clash here stops the rig.
• Entry and exit structures: stairs, lifts and escalator pits, often on the footpath where telecom and power ducts run.
• Ancillary buildings: ventilation shafts, chiller plant and substations in side roads or plots.
• Diversion corridors: the streets that will receive moved services, surveyed so the new route is clear.

How is the survey carried out on a live arterial road?

In stages, mostly at night, with traffic police and road-owner permissions arranged by the project. The sequence that works is:

1. Records collection: drawings from the water utility, sewerage board, DISCOM, telecom operators and gas distributor, gathered with our checklist.
2. Surface inventory: every manhole, chamber, valve box and marker is fixed by total station, and opened where the owner allows to measure inverts.
3. Locator tracing: metal pipes and cables are traced by direct connection or by induction.
4. GPR grid: ground penetrating radar lines cross the road at agreed spacing, tighter on the wall line, to catch non-metallic pipes and ducts. The radar times the echo of each pulse to give depth.
5. Trial pits: hand-dug or vacuum excavated where the diversion design depends on exact depth, mostly at wall-line crossings.
6. Grading: every line gets a confidence tag under the quality levels, running from records only up to seen in a pit.

Night work keeps lane closures short. A crew can cover one carriageway of a station length per night once barricades are up; footpaths are done in daytime.

What does the design team receive?

A layered drawing in the project coordinate system, ready for the diversion engineer to overlay the station layout. We work to the grid and datum the general consultant fixed, so the utility data drops straight onto the structural drawings. A closer look at CAD and GIS utility mapping explains how layers, attributes and line styles are set up.

Table note: if the station also needs road levels, kerbs and surrounding plots for the layout, we pick these up with the same control; see booking land survey services.

Which problems come up most at metro stations?

Unrecorded telecom ducts, sewers deeper than the records say, and services already diverted once. Many arterial roads were widened in the last twenty years, and services moved then were not always redrawn. Old cast iron mains often stay live beside their replacements, and joint bays hide under footpath tiles. Private connections from shops and petrol stations cross to the far side.

Footpath zones deserve special care, because entry structures sit on them over the shallowest, most crowded services. New connections appear between survey and construction, so every excavation there should follow the steps you can read more on call before you dig in India.

Where does the survey sit in the station programme?

Ideally twice: once at design stage to shape the layout, and again shortly before mobilisation to catch anything new. Months can pass between tender drawings and the first barricade, and a road with heavy services seldom stays still that long.

The first survey answers design questions. Can the entry shift three metres to avoid a trunk sewer? Should the 33 kV cables be diverted once around the box or in stages? Should the water main be supported in place instead of moved? Such utility coordination is far cheaper on paper than on site.

The second, lighter pass checks the wall line and entry pits before construction. It picks up new telecom ducts, fresh house connections or a repair that moved a joint, and often saves a week lost to an unexpected cable.

After diversion, the moved existing utility lines need recording, because the old drawing is now wrong in a new way. That record becomes the base for the station's own utility map once it opens.

Rates, timeline and how to start

Station surveys use our standard GPR rate card, applied to the total length of scan lines across all zones.

• ₹24 per metre for standard scanning, ₹32 per metre where an L-section profile is required.
• Minimum order ₹50,000 in Delhi NCR and ₹1,00,000 in other cities.
• Corridor packages: 25% off the whole order above 100 km of scan, 40% above 500 km, 50% above 1,000 km.
• GST extra; the written quote fixes the amount for the zones agreed.

Field time for one station is three to six nights depending on width and permissions, with drawings about three working days after the last shift. Delhi NCR stations get a crew on the order day or the next working day. In any other metro city, our resident engineer begins at once, never later than one working day after the order. Travel or mobilisation, if applicable, appears as a line in the quote. For the diverted lines, ask us how long an as built survey takes. To set limits and dates, start a survey enquiry with the station layout and zones.

Station scans come to Mezux Touch from DMRC and NCRTC directly, and from the civil contractors and consultants in each project team.

Frequently asked questions

How far beyond the station box should the survey extend?

The design consultant fixes it, but a buffer of several metres beyond the wall line plus the full diversion corridor is common, so new routes are checked as well.

Can you work in the project's coordinate system?

Yes, we tie to the control points the general consultant provides, so the utility drawing overlays the structural drawings directly.

Do you open manholes?

Where the owning agency allows it and the project arranges access, yes. Invert levels from opened chambers are far more useful than cover levels alone.

What do the deliverables look like?

There is a short guide on GPR survey deliverables with sample layers, sections and registers.

Can elevated and underground stations be surveyed the same way?

The method is the same, but the zones differ: pier foundations and median strips for elevated stations, the full box and wall line for underground ones.

Who digs the trial pits?

The civil contractor under the project's permit, by hand. We mark the locations, attend and record each pit.

Written by Saniya Parveen · Technically reviewed by Rahul Rai · Updated 8 November 2026