BENGALURU: The first Metro train, which began operating in Bengaluru in 2011, is hard to distinguish from the most recently obtained coaches.

With the only observable difference between the 2011 train and others is the serial number marking the procurement details, most Metro users might agree that its 50 trains and 64 stations are spick and span.

Across its 70-km network, the machinery and plant department of the Bangalore Metropolitan Rail Corporation Limited completes automatic washing and internal (heavy) cleaning of all trains over a two-week cycle, apart from the daily routine cleaning.

TOI visited Metro's Byappanahalli depot to witness the department's three distinct cleaning processes.Automatic washing plant The unidirectional automatic washing plant (AWP) takes a train through six brushes and loops where a combination of freshwater and recycled water rinses the exterior along with timed splashes of industrial steel-cleaning detergent.

AWP takes care of the trains' exterior cleanliness and switches between washing only the sides and the front and top as required.

"There are 24 trains on the Purple Line that get washed here while the other 26 trains are washed at Peenya depot.

It takes our depot three days to complete automatic washing of all 24 trains.

At the end of the loops, we have side and roof blowers that dry the train and it is all cleaned up for its next round," said E Anandan, assistant executive engineer (rolling stock).