The document summarizes a rail and road viaduct extension project in Tuas, Singapore called the Tuas West Extension. It extends an existing east-west rail line by 4 km. VSL Singapore was contracted to design erection equipment and perform all post-tensioning work. The author was the gantry engineer in charge of one rail gantry for 7 months, providing consultancy and on-site supervision to optimize construction cycles and ensure compliance with the approved design.

1. Vaimiti RIGAL 1/2 January 2015
TUAS WEST EXTENSION VIADUCT
(Singapore)
Designer: AECOM
Main contractor: China Railway Bureau 11
Viaduct and post tensioning specialist: VSL Singapore Pte Ltd
1) The project
The Tuas West Extension is a road and rail viaduct project owned by the Land Transport
Authority (LTA) of Singapore. It extends the existing East – West Mass Rapid Transport (MRT) rail
viaduct westwards by 4 km, in Tuas.
The typical viaduct section is a higher level twin track rails with lower double lanes vehicles
carriages ways on both sides of the column, as shown below. The equipment planning is 4 rail
gantries and 2 road gantries to operate simultaneously.
VSL Singapore is contracted to China Railway 11 Bureau Group Corporation (Singapore
Branch) (CR11) to undertake the works for design of erection equipment for the cross heads, rail
viaducts, and road viaducts. The company is also in charge of all post tensioning works and site based
consultancy.
2) What I was involved in
As gantry engineer, I was in charge of one rail gantry for a period of 7 months. My scope
included:
- Consultancy follow up:
o Suggestion reports to the main contractor to highlight potential improvement
(schedule of delivery of precast segments, permit to work submission, manpower
planning, mechanical issues anticipation),
o Preparation of the submissions for site design amendment request due to non
conformance of site works, such as:

2. Vaimiti RIGAL 2/2 January 2015
 Adjustment of the overall tension in one span due to a wrong choice of
anchorage (anchorage for 6-19 strands instead of 6-22 for example),
 Alternative anchorage system on the crosshead due to missing tie-down
cast-ins,
o Cycle optimization suggestions and procedure to reach the targets.
- On site supervision:
o Compliance with the design approved during assembly,
o Testing and commissioning of all functions including pumps before and while first
span erection,
o Audit of the production cycle.
Here are some pictures during progress: