Calcutta: Businessman Manmohan Kohli dreads running into escalator downtime during his daily commute till Chandni Chowk Metro station, where climbing a steep flight of stairs requires a massive effort from a 69-year-old who had a bypass surgery six months ago.

Kohli, who boards his train at Netaji Bhavan, has had to struggle the past 10 days because the escalator going up till the exit towards Indian Coffee House is shut for repairs. The other way out to reach his destination, a store behind the erstwhile Orient Cinema, involves climbing more than 50 stairs.

He takes seven to eight steps up at a time, rests for a while and then resumes his climb.

Kohli isn't the only one. Scores of elderly commuters suffer every time one or more of Metro Railway's aged and ailing escalators malfunction. One such escalator at Dum Dum station suddenly reversed direction on Tuesday morning, throwing off several commuters and leaving one of them with injuries to both knees.

The majority of escalators are from a platform till the concourse. Only 15 of the 47 escalators at 18 underground stations are from a mezzanine floor till an exit. Even the busier stations like Esplanade, Chandni Chowk and Park Street do not have escalators till all the exits.

At Esplanade, which has eight exits, there are four escalators from the platform till the mezzanine floor and only two from there till the road level. Kalighat has 10 exits and two escalators that go from the platform till the mezzanine floor. There is not a single one that goes all the way up.

"It is difficult to modify civil engineering structures at the older stations. As of now, there is no plan to install additional mezzanine-to-surface escalators in these stations," Indrani Banerjee, the spokesperson for Metro Railway, said.

Apart from senior citizens, people with disabilities have difficulty at stations that don't have escalators till any of the exits.

Rupa Chakraborty, who teaches botany at Dinabandhu Andrews College in Garia, struggled to climb the stairs at the Jeevan Deep exit of Maidan station on Wednesday afternoon. The assistant professor, who has rheumatoid arthritis, was going to a nursing home for a check-up. "My driver took the day off today. Thank heaven there is at least one escalator here," she said.