Dubai Metro trains undergoing complete overhaul

Rolling stock technician Nisath Devage works on the undercarriage of a train at the Dubai Metro depot in Al Qusais. Alex Atack for The National

DUBAI // From brake panels to batteries, wheel components to pressure gauges, the insides of the Dubai Metro’s trains are being taken apart and examined for safety as part of rigorous maintenance procedures.

Trains that have run 600,000 kilometres are being brought to the Al Quasis depot for a complete overhaul that can take up to a month.

“Every single piece of the big train is tested. Since our trains are driverless, every single issue related to operation is automated so each part is put through inspection, all valves and components go through different levels of pressure to be sure it is capable to go through this threshold,” said Abdul Mohsin Ibrahim Younes, chief executive of the Roads and Transport Authority’s Rail Agency.

“In the overhaul we dismantle everything. Some parts can be used again, if any leaks or defects are found, these parts are replaced. Everything from the components of the braking system, valves, electrical switches are examined to make sure it is safe before fixing them back. The engineers make sure there is no problem in terms of operating the system. This is to keep the trains up to the highest level of reliability and maintain safety standards.”

Regular maintenance is carried out daily with work also scheduled every fortnight, at three month intervals and yearly detailed inspections. The major overhaul procedures where trains are stripped open began last year once the machines hit the 600,000km mark.

Of the 79 trains, the first batch of 16 have been rigorously checked with 28 due for an overhaul by October next year. Two trains are brought in at a time for the exhaustive process that can take three weeks to complete.

All electrical and mechanical components from the smallest screw weighing a few grams to multi-tonne wheels and bogie, or undercarriage, are removed from the blue and silver coaches.

“Just because it is a small screw, it does not mean the component is not important. An international standards must be maintained for every part because it is important for operation. These are safety critical issues,” Mr Younes said.

About 26 people work in the huge depot where turntables and rails take the various equipment parts to testing machines. The components are laid out on wooden frames tagged, labelled and coded with the train number.

In the workshop, workers wearing helmets and masks bend over the tables to disassemble motor units or check pressure in valves.

In one section, workers scrutinise levelling valves that keep a train steady and in line with the platform irrespective of the load of passengers who exit or enter.

“If this level is not right, then the train can go lower than the platform and people may fall down, our trains are automated so the valves that keep the train up to the level of the platform must be checked,” Mr Younes said.

At another end, workers inspect the power traction engine, described as the train’s heart. Supervisors tick cards with a green box indicating healthy and a red marked as defective depending on the performance of each unit.

“The testing done is similar to an operational scenario to put all the parts through the same conditions,” said Mohammad Al Amiri, the deputy director of rail maintenance.

The weather also plays a part in the wear and tear with components requiring quicker replacement.

“Some equipment we may need to change based on the environment, especially in the summer because of the sand, the high humidity during the day and night.”