Case study · Rail

PRASA Walling Project

Setting-out and as-built surveys for about 36 km of 3 m high concrete walling along Gauteng railway corridors.

Place: Priority railway corridors, Gauteng
Client: Passenger Rail Agency of South Africa (PRASA)
Our role: Surveying and setting-out for wall construction

A survey crew in hi-vis vests working next to a railway line

Overview

As part of its infrastructure rehabilitation and modernisation programme, PRASA is building reinforced concrete walls, 3 m high, along key railway corridors in Gauteng to stop unauthorised access, cut vandalism and theft, and make commuting safer. The walling sits inside a wider security strategy that also covers more security staff, upgraded signalling, and the refurbishment of stations and lines. Geovantage is contracted to provide the surveying for the wall construction. Our current scope covers stretches totalling about 36 km of wall.

Quick factReinforced concrete walls over 3 metres high are being built along priority railway corridors to curb vandalism, theft and unauthorised access.

Corridors and scope

The walling program covers multiple priority corridors, with initial focus areas including:

Geovantage's current scope involves surveying stretches totalling approximately 36km of wall construction across these corridors.

Mabopane Corridor: High-risk area with significant commuter traffic; part of a R7.2 billion rehabilitation initiative
Central Line: Key link in the Gauteng network targeted for security upgrades
Wolmerton to Winternest & Wolmerton to Pretoria North: Sections with known illegal crossings

Challenges

Operating in live railway environments with safety and access constraints
Maintaining accuracy over long, continuous wall alignments
Coordinating with multiple construction teams across dispersed work sites
Surveying in varied terrain, including urban, peri-urban, and vegetated areas

Our approach

Geovantage deployed a mobile survey team equipped with GNSS RTK rovers and total stations to handle the high-accuracy demands of wall setting-out. Our methodology included:

Establishing a unified control network for all wall sections
Marking wall alignment and foundation positions at precise intervals
Conducting as-built surveys after excavation and before concrete placement to confirm compliance
Integrating survey data into PRASA's construction records for quality control and project management

Technology and deliverables

Instrumentation

GNSS RTK Systems: for rapid, high-accuracy positioning along long corridors
Robotic Total Stations: for setting-out in areas with obstructions or tight tolerances
Digital Levels: for elevation control over extended distances

Deliverables

CAD alignment drawings and coordinate registers
As-built survey reports for each section
Progress tracking reports with supporting survey data and photographs

Outcome

Setting-out and verification over 36 km of construction helps the walling get built to design and on schedule. The work supports PRASA's goal of securing its network and improving passenger safety.

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