Putting Mumbai Monorail on track

The Mumbai Monorail project is the first-of-its-kind in India, built by an L&T-led consortium, using the AutoCAD Civil 3D software for optimised productivity, time and resources
Having secured the Rs. 2,460-crore order from the Mumbai Metropolitan Region Development Authority (MMRDA), a consortium led by Larsen & Toubro (L&T) with Malaysian-based Scomi Engineering Bhd has implemented a pioneering development in Mumbai.
Unlike conventional rail systems, where the train runs on dual tracks, the monorail operates on a single beam (also known as a guide beam) on an elevated corridor. It’s considered amongst the world’s most urban transport systems. In the urban context of India, especially Mumbai, where land resources are scarce, the monorail project duly assumes immense significance as it requires smallest footprint. It’s eco-friendly, low on cost and free of noise pollution. The straddle type monorail system, equipped to carry 2 lakh passengers per day, complies with the highest international standards of safety and reliability besides allowing high manoeuvrability by negotiating sharp curves and handling curves up to 6 per cent. It’s expected to decongest the highly crowded areas of Jacob Circle, Wadala and Chembur and link Mumbai’s west and northeast corridors. The 19.54 km-long monorail project will have 18 stations in its route as well as connect the existing suburban railway system and the forthcoming metro rail as part of a multimodal transport system.
For the L&T-led consortium, the scope of the project covers design works, development, construction, manufacturing, supply, installation, integrated testing and commissioning, and requires completion within a tight schedule. It is being implemented on a fast-track basis as the design facilitates execution with minimal demolition of structures. Given the strict confines, each of the project stakeholders heads a distinct responsibility. With Scomi Engineering involved as the design and technology partner, L&T has engaged three of its divisions — Railway Business Unit, Engineering Construction & Contracts (ECC) and Integrated Engineering Services (IES) — for the geometric detailing and construction of the monorail track. While L&T ECC prepares detailed construction drawings and documents besides executing construction work for this project, L&T IES produces 3D geometric models of the guide beams along the alignment to extract global, erection and casting coordinates for shop drawings.
The consortium 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 among many teams and stakeholders. The consortium chose to adopt AutoCAD Civil 3D software, a comprehensive product for the design, drafting and management of a range of civil engineering project types involving complicated geometry even in 3D spaces, including challenging transportation projects.
ChallengeThe Mumbai Monorail project proved to be intricate at many levels beginning with its geometric design and its inability to find the appropriate technology to address it. In its initial phase, a partner additional to Scomi Engineering designed the entire guide beam line profile, the beams and other details. It was imperative to transfer this complex geometry, correctly and accurately to the team at L&T ECC, which 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 Swaraj Datta Gupta, Head IES – Construction Engineering, L&T Ltd. “With L&T-Scomi having not received the geometric profile of the individual components of the entire line of guide beams from their design partner, IES Construction Engineering was entrusted to do the geometric work for all these guide beams. This was a big challenge,” he adds.
Complexity of geometric designContrary to 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 radically different. It needs to consider both top and bottom profiles for its geometric design, a complexity that was compounded further by the lower part of the beam not being circularly curved but parabolic in nature.
Arun Varadhrajan, Project Leader Engineer, explains, “Our project was to get the total line layout from L&T-Scomi and the design partner, which would in turn give us the pier locations and the individual guide beam profiles along the line. Only then could we deliver both, the casting as well as erection coordinates for each and every guide beam along with its local coordinates.”
Lack of appropriate, customisable softwareThe lack of appropriate software created a huge gap. “All existing software was mainly for roads and highways, and since a monorail project profile is very different we were looking for software that could be customised for this project,” explains Mr Dutta Gupta. Other geometric software were not flexible enough to address the complexity of the geometry of the track profile, varying cross-section from rectangular to skewed and reverse to maintain track super-elevation, further complexity added with parabolic soffit of the guide beams.
SolutionAutoCAD Civil 3D software, the building information modelling (BIM) solution for civil engineering, helps teams deliver high-quality transportation, land development and environmental projects faster. Its model-based approach helps keep project information coordinated while delivering high-quality documentation and visualisation. 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 optimised 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.Achieving geometric parameters with a high level of accuracy
“I don’t think we would have been able to execute the monorail project without AutoCAD Civil 3D,” says Mr Dutta Gupta.
The software helped the project team take into account components of variation for individual beams, which are each 850-mm wide and 2,000-mm in depth. 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. The software helped the team achieve the requisite level of accuracy up to 1 mm per metre, setting a definite precedent for all future monorail projects in the country.
Optimisation of time and resourcesAutodesk software shapes itself as a common design platform that allows teams to collaborate and share project data effectively. Given that different divisions of L&T were already using Autodesk software such as AutoCAD as a basis for 2D design, detailing and documentation; the deployment of AutoCAD Civil 3D for the monorail project created an optimum advantage because it allowed a solution within the Autodesk environment. Against the need for a whole new training cycle for the team, it required only an incremental learning to their existing understanding of current tools. The design-centric approach of Autodesk differentiates it from most software solutions in the market that use a document-centric approach. While the initial time taken to build the standards and processes is a little high, when it comes to reusability of the same data, the user stands to gain considerable advantage.
Easily make changes and minimise errorsConsidering that this was a fast-track project with simultaneous collaboration among multiple stakeholders and several iterations involved during the design-to-execution stages, the advantage of AutoCAD Civil 3D software’s dynamic model-based design and its scalable, attainable and reusable technology became a pivotal link among the survey, design, and drafting and execution teams. This approach allows the process of design, visualisation and simulation to be developed at its convenience, wherein any change automatically factors into the other parameters. As it evolves as a digital prototype and accommodates changes digitally, the margin for error in a time-bound project can be minimised.
Interconnectivity between design and draftingOne of the challenges of the project was the replication of design from paper output into reality, and AutoCAD Civil 3D was the only tool that facilitated the translation of hard copy into actual coordinates. “Although creating profiles was not in our scope of work, we needed to create designs on our own, in the interest of maintaining the tempo of the project. In some cases we did not receive the actual profile from the principle designer but by using AutoCAD Civil 3D we could generate these just from the end points, tangent points or transition points,” explains Mr Datta Gupta.
ResultUsing AutoCAD Civil 3D, the Mumbai Monorail project has literally and figuratively fast tracked its success story. “I do not know whether we could have done it without AutoCAD Civil 3D. There is no match to its capabilities. The only other alternative was that we would have to do it manually using basic data analytics tools, and that would have certainly been laborious, time consuming and, needless to say, cost ineffective,” says Mr Datta Gupta.
“Autodesk technology played a significant role in the building of the first-of-its-kind monorail project in the country,” says Sunil MK, Head – AEC, Autodesk, India and SAARC. “The L&T team leveraged a fully customised software solution that helped visualise, simulate and analyse the real-world performance of the project early in the planning process. It also helped achieve seamless collaboration among stakeholders and reduction in errors from project design to project implementation. We are extremely happy that Autodesk technology was instrumental in two landmark projects of India – T2 and Mumbai Monorail – conforming to international standards.”
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 metre and accomplishing 80 per cent time optimisation in deliverables. Today the team is able to deliver one beam of 25m length within 30 minutes, including the quality checks and everything.

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