Putting Mumbai Monorail On Track

Autodesk AutoCAD Civil 3D has established India’s first monorail project as a precedent for achieving a level of accuracy of up to 1 mm per meter and accomplishing 80 percent time optimization in deliverables

The Mumbai Monorail project is the first-of-its-kind in the country, built by an L&T-led consortium, using the AutoCAD Civil 3D software for optimized productivity, time, and resources. Unlike conventional rail systems where the train runs on dual tracks, monorail operates on a single beam – called guide beam – on an elevated corridor. It’s considered amongst the world’s most modern urban transport systems. In urban India, especially Mumbai, where land resources are scarce, the monorail project duly assumes immense significance, as it is seen as a viable option since it has the smallest footprint, is eco-friendly, low-cost and free of noise pollution. The straddle type monorail system, equipped to carry two lakh passengers per day, complies with the highest international standards of safety and reliability besides allowing high maneuverability by negotiating sharp curves and handling curves up to 6 percent. It is expected to decongest the highly crowded areas of Mumbai like Jacob Circle, Wadala and Chembur and will link its west and northeast corridors. The 19.54 km long monorail project will have 18 stations in its route and will also connect the existing suburban railway system and the forthcoming metro rail in the city as part of a multimodal transport system.

Fast Track Project For the consortium, the project covered design works, development, construction, manufacturing, supply, installation, integrated testing and commissioning, all within a tight schedule. It is being implemented on a fast-track basis as the design facilitates execution with minimal demolition of structures. The project needed software that would help meet the challenge of building this first-of-its-kind monorail project in the country within stiff timelines and standards to also help bridge the multi-pronged simultaneous collaboration between the many teams and stakeholders. The consortium chose to adopt AutoCAD Civil 3D software, a comprehensive product for the design, drafting, and management of a wide range of civil engineering project types involving complicated geometry even in 3D spaces — including challenging transportation projects.

Complexity of Geometric Design
The Mumbai Monorail project was challenging at many levels, beginning with its geometric design, and its inability to find the appropriate technology to address it. Initially, the entire guide beam line profile was designed with the beams and other details. It was imperative to transfer this complex geometry correctly and accurately to the execution team at L&T that was entrusted with the actual construction. “The construction team needed these details not only to cast the beams but also to erect them in the required actual and ultimate line profile,” says Mr Swaraj Datta Gupta, Head IES – Construction Engineering, L&T Limited.
Unlike roads and highways that are single entities with a top surface and can be seen only from the top two points, an individual track or guide beam profile is different. The top and bottom profiles of its geometric design needed to be considered. This was compounded further by the lower part of the beam which was not circularly curved, but parabolic. Imagine a 3D line, which may be curved or have a super elevation or be straight, that also has a bottom profile where the soffit has a bit of a vertical curve apart from the profile curves. This needed to be brought down to its coordinates on the ground level for effective casting. In both cases, all four coordinates across the cross section on all four corners, starting every 500 mm from the pier location, were needed.

AutoCAD Civil 3D Software
The lack of appropriate software created difficulties. Research indicated there was no solution exclusively designed for monorails. All existing softwares were mainly for roads and highways, and since a monorail project profile is very different, we were looking for software that could be customized for the project. Other design softwares were not flexible enough to address the complexity of the track profile’s geometry, varying cross-section from rectangular to skewed and reverse to maintain track super-elevation. Parabolic soffit of the guide beams added further complexity. One of the biggest challenges was the need to reuse information from drawings.
AutoCAD Civil 3D software, the building information modeling (BIM) solution for civil engineering, helps teams deliver higherquality transportation, land development, and environmental projects faster. Its model-based approach helps keep project information coordinated while delivering higher-quality documentation and visualization. AutoCAD Civil 3D helps users gain the competitive advantage of BIM to deliver more innovative project solutions. Its key new features include scalability and performance improvements, as well as an optimized 64-bit version of Civil 3D tools to better manage the creation and editing of corridors, and enhanced super-elevation functionality that provides a dynamic link to the alignment and flexible editing options.

High Level of Accuracy
The software helped the project team take into account components of variation for individual beams, which are each 850 mm wide and 2000 mm deep. Each of these components has been put together to create a curvilinear space in the air, viewed after construction as aesthetic curved rails running above the ground.
Between designing a curvilinear path to measuring it in space in order to make the actual construction happen – there is a vital link between design, engineering and construction. The software helped the team achieve the requisite level of accuracy – up to 1 mm per meter, setting a definite precedent for all future monorail projects in the country.  AutoCAD Civil 3D has established India’s first monorail project as a precedent for achieving a level of accuracy of up to 1 mm per meter and accomplishing 80 percent time optimization in deliverables. Today the team is able to deliver one beam of 25m length within 30 minutes, including the quality checks and everything. The software allowed redefining of design processes, spurring innovation, achieving competitive advantage and enhancing overall productivity, and profitability.