When 26-year-old Chamkour Singh wanted to become a cabby in 1978, he needed $30,000 - a sizeable amount considering that his Clementi flat cost $12,000 back then.

With a bank loan and family support, he managed to put together the $20,000 needed for a brand- new Datsun, and another $10,000 for a yellow-top taxi licence.

Mr Singh struggled to pay off the debt in the first two years - spending up to 16 hours a day on the road - but working as a cabby allowed him to put his two children through university.

Today, 65-year-old Mr Singh is among a vanishing breed of cabbies who privately own and operate their cabs, unlike the majority who rent their cabs from companies.

Although, like all in the profession, they have to get the taxi driver's vocational licence, they don't pay rent and don't have to meet an operator's taxi availability standards. Also, unlike other drivers, they pay for their own cab's certificate of entitlement.

He said: "With your own taxi, you have more freedom. When you rent from a company, you have to adhere to their rules and regulations... Having a yellow-top is like having your own house."

As of last month, there were only 100 such cabs - called yellow-tops for their distinctive yellow roofs. This accounts for close to 0.4 per cent of the total taxi population of more than 26,000. In the 1960s, the 3,800 yellow-tops were synonymous with taxis.

A spokesman for the Land Transport Authority said the average age of the yellow-top drivers now stands at 67.5 years. In comparison, the average age of the general cabby is 55 as of two years ago. The last yellow-top taxi will be phased out in 15 years' time, as the younger drivers in the group hit the age of 75, the age ceiling for cabbies.

Their decline can be traced back to the 1970s, when the Government changed its policy to issue taxi licences only to entities, rather than to individuals. Subsequently, it was mandated that the licences were non-transferable.Street smarts and experience keep their wheels rolling in the face of stiff competition from private-hire car services.

Mr Tan Cheong Shiaw, 64, who started driving a yellow-top in 1979, said in Mandarin: "There are fewer customers hailing cabs on the road now. A lot of young people and professionals like to use the mobile phone to call for an Uber.

"But there's still business. At least $40 to $50 in profit every day. On a good day, $70 to $100," added Mr Tan, who plies the roads from 6am to 5pm daily.

Mr Quek Chin Poh, 64, a part-time yellow-top cabby, described his tactic: "If I see potential customers standing by the kerb holding their phones trying to book a ride, I'll drive by slowly, and sometimes they will take my taxi in the interest of time."

Yellow-tops were brought in by Wearne Brothers, the predecessor of automotive dealer Wearnes, and first hit the roads in May 1933.

Industry veteran Neo Moh Hock, 65, the owner of Beach Road Radio Taxi Service, feels that yellow-top taxis should be preserved because of their legacy.

"There's a story to tell of the first taxis in Singapore," he added.

Mr Singh is adapting to the new landscape, registering with Grab to take bookings through the app's GrabTaxi service. He said: "It has helped me a lot. If I ferry a passenger to Tuas, there's a chance I can get a passenger on the way out, with a GrabTaxi booking."

He has had to work hard and manage his finances so he can pay for the annual road tax, insurance, maintenance, and also a new taxi every eight years. He purchased a new Toyota Wish last December, which will be his last yellow-top taxi.

Looking back, he said: "I don't regret it. The taxi has given both my children a good education... and it also supports my hobbies of golf and tennis."