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Dubai: showcase for the Gulf?

It is 10.6km (6.6 miles) long and uses Alstom Citadis trams. Such a statement could make the Dubai Tramway appear pretty ordinary – but that’s one thing it certainly is not.

The new light rail line opened in November 2014, under a ‘turnkey’ contract with Alstom that includes maintenance for 13 years. Like the Gulf State’s metro, the tramway is operated by Serco, under a deal signed in 2013 that included a period of preparation then five years of operation. The tramway is part of a programme intended to move public transport take-up from 15% to 30%.

Situated on the Persian Gulf, Dubai has a hot – and sandy – climate. Those things themselves create technical challenges, but the line also brings together various innovative features in one place. Most eye-catchingly, it is the first modern tramway of its kind to be completely wire-free over its whole service length, using Alstom’s Alimentation par le Sol system of ground-level current collection.

More prosaic things mark it out too: “It’s the first tramway in the Gulf,” explains Alstom’s Managing Director GCC countries and Project Director of Dubai Tram, Vincent Prou, “The first challenge is to incorporate a tramway into a city that has never seen such a system before and also to integrate with quite a few stakeholders.

“It’s the first of its kind in many respects. Full APS along the line is an important one,” says Prou. “You have to manage temperatures of 50°C, which on the roof [where much of the trams’ equipment is located] can reach 80°C. You have to manage sandstorms, you have to manage humidity and corrosion because you are next to the sea.”

Perhaps it’s no surprise then, as Prou explains, that Alstom “had to re-engineer a number of key aspects.” These included relatively prosaic things as well as the more headline-grabbing features. For example, compared to other markets, the trams’ heating, ventilation and air conditioning (HVAC) systems had to be increased in size to cope.

Dubai’s harsh climate also had a key influence on the design of stops, which are quite different to the more basic calling points common in many places across the globe. Here, explains Prou, the line has fully enclosed passenger stations “which in turn imposed something new for a tramway, automatic platform screen doors. They are very exposed to the environment.”

In order to judge the effects on the doors over time under these difficult conditions, Alstom built a ‘mock up’ station to try it out.

“We replicated the kind of passenger station and we recreated the operation for ten years,” said Prou. “We had the doors opening and closing every ten seconds to come up with millions of cycles.”

However platform screen doors were not the only aspect of the new line subjected to rigorous testing. Indeed, a whole 44m tram was taken to be thoroughly tested in the Rail Tec Arsenal climactic wind tunnel in Wien (Vienna), Austria; Alstom has a stake in the state-of-the-art facility, which also includes Bombardier and Siemens among its shareholders.

“We recreated in the climactic chamber the exact conditions of Dubai…” explains Prou, “and we tested the performance of the equipment.”

“Of course we had done a number of software simulations before that… and luckily enough, the results in the climactic chamber were quite conclusive and successful.”

Initial experience in the period following opening appeared to have borne out that work, says Prou: “We can already say we have been through the hottest months of the year without any surprises, and very successfully.”

Catenary-free operation

One of the major innovations is use of Alstom’s APS throughout the public section of the tramway, a decision taken on aesthetic grounds. It’s a first – quite aside from it having to work in a harsh environment.

“We knew this would be a major challenge,” says Prou. “Although APS ‘first generation’ is fully proven, we knew we would have to go to the next generation. We have completely re-engineered it.”

That has not only been about ensuring the system can put up with heat and dust because, as Prou explains, “there are heavy floods in the region.”

“We had to ensure that the power boxes themselves can be immersed; we have also paid great attention to the way we drain the whole platform.”

Nevertheless, dust – or rather sand – was indeed a major complicating factor, given that trams using APS pick up electricity from ground level.

“We had to analyse the effect of the sand. We incorporated a heavy duty brush under the tram, and then in the laboratory we tested the choice of material on the contact shoe to check the wear on this interface. We used actual sand from Dubai… to ensure we had the exact same sand.”

Other innovations are less visually obvious than the lack of overhead catenary or the enclosed stations – or indeed aspects such as the fact that the tramway runs almost exclusively on its own segregated formation, except at the signal-controlled highway crossings.

Given the need for supreme accuracy in driving and the challenge of ensuring tram doors line up precisely with platform screen doors at stops, the Dubai Tramway has been equipped with a form of signalling more associated with metro systems: Alstom’s Urbalis 400. This is a Communications Based Train Control (CBTC) system, and provides speed control along the line, interlocking protection at signals and stopping accuracy at stations with applied braking profile.

“This is really something new,” says Prou, “the traditional principle of driving at line-of-sight is still applicable like on any other tramway but other features are new and bring enhanced safety to the system.”

One stop shop

In all this, Alstom has acted as the leader of a consortium to provide a ‘one stop shop’ for the customer, Dubai’s Roads and Transport Authority. Although the EUR700m project has included fielding many of its own products, it has also meant the French conglomerate working with others. The Belgian company BESIX undertook civil engineering aspects such as utility diversion, building construction, and creating the elevated section of line running on a 2.5km (1.6-mile) viaduct.

Giving some idea of the range of what has been covered in the creation of the new line, Prou explains that “we had within our scope of work a number of studies and analyses that traditionally would be delivered by engineering companies before [the authorities] issue the tender.”

Examples are Urban Insertion Studies, passenger flow analyses, road traffic flows analysis, and Station Context Planning.

He adds that work has also “regenerated the urban environment by recreating landscapes – examples including the cycle track that runs parallel to the line”. The result is very much appreciated by the residents and commuters.”

Prou seems pleased with the performance of the Dubai scheme, and pays credit to the entire team that created it – including the customer.

“We have delivered the whole project ahead of schedule – nearly two months early,” he says, adding, “And the introduction into service has been very smooth.”

Indeed, it is clear that Prou sees the Dubai line as a possible beacon for others. “We will… drive a lot of experience into the next project we have secured, which is Qatar.”

“We hope that Dubai can be a real showcase for the rest of the region.”

From a feature originally published in Tramways & Urban Transit –  May 2015 issue (928)