Dubai Metro: Feat underground

With the launch of Dubai Metro barely 15 months away, the Roads and Transport Authority (RTA) has pulled out all the stops to ensure that safety measures are in place.

The media was given a glimpse Tuesday of the several key mechanical features that will prevent loss of life if tragedy should strike the twin-track system.

Guard rail

One of the safety aids will be a guard rail that will run alongside each track on which the Metro’s five-set trains operate at 22 metres below ground level.

Anthony Burchell, Project Director for project engineering contractors Systra and Parsons, said in a brief interview while walking the one-kilometre tunnel between Union Square and Al Rigga stations that "if a train derails, it should prevent it from jumping into the path of the oncoming train on the other side".

"The guard rail is a big safety item that will keep Metro riders safe in years to come," he added.

Structural integrity

The way the guard rail will work is that if a moving train jumps off its track, the guard rail will contain it to the designated side of the tunnel preventing a head-on collision between trains.

During the tour, Burchell pointed to a continuous stretch of L-shaped rebar links stemming from the floor of the tunnel – when the main track is installed, the rebar will reinforce the concrete forms that support both the track and the guard rail.

Another safety feature built into the Metro infrastructure, Burchell said, is an ingenious addition of not just one, but two gaskets around each of the crescent-shaped concrete segments that form the tube walls.

When the segments were put together like pieces in a jigsaw puzzle to form the inner concrete tunnel tube, the gaskets virtually cemented themselves together creating a solid rubber-like vapour barrier to prevent water from seeping into the structure.

Keeping the underground tube dry not only ensures the structural integrity of the tunnel rings but also keeps the electrical fittings and the main train rails relatively free from risk of shorting out.

"We used this first in Cairo, then in Singapore and now we have a completely dry tunnel here in Dubai. The system really works," Burchell said.

Escape hatches

A third major safety component has been incorporated into the Metro tunnel system to deal with any underground fire – escape hatches built directly into the tunnel walls.

Burchell said the safety annexes will not only allow fresh air in through shafts extending from the ground surface but will also act as exhaust vents to allow smoke out.

Passengers can also use the escape shafts to exit the tunnel.

The annexe in the tunnel between Union Square and Al Rigga station is similar to the annexe in the stretch of tunnel between Union Square and BurJuman Centre, Burchell said.

Control Centre

The Rashidiya Depot will become the main home base for the Metro. A dozen major buildings are being erected at the depot which is now 60 per cent complete.

The depot will be the place where trains will be repaired, washed, tested and driven from a central operating control and administrative centre, the "heart and brain" of the system, said Namzi Kaner, Senior Project Manager Depots with JT Metro JV.

The control centre is being set up on the first floor of the 10,000 square-metre facility which will be known simply as Building 11.

"This will be the most prestigious building with the Metro," said Kaner.