An Alexander Dennis Enviro500 in KMB livery

Hong Kong’s largest franchised bus operator KMB has placed an order for 72 diesel-powered Enviro500 double-decker buses from Alexander Dennis in the UK, with no word on the timeframe for delivery.

The order includes 46 of the longest version of the Enviro500, a 12.8 metre double-decker with a capacity of 144 passengers; and 26 of the shortest in the range, an 11.3 metre double-decker capable of carrying 124 passengers.

According to maker, the bus is the “world’s best-selling high capacity double decker” with around 18,000 in operation around the world.

KMB has purchased around 2,500 of the three-axle Enviro500 series buses from Alexander Dennis since the model was launched in 2012.

News of the major diesel bus contract comes a couple of months after rival Bravo, which operates CityBus and NWFB, announced its first electric double-decker had cleared customs and was going through approval processes in Hong Kong.

That 12-metre-long bus, a joint venture between mainland firm Wisdom (Fujian) and Bravo Bus, is currently undergoing acoustic testing by Environmental Protection Department before Transport Department will test safety and road-worthiness.

Bravo is also exploring the idea of hydrogen buses, after a government pledge to put hydrogen buses on the roads “within three years” this October.

“We believe that hydrogen provides a practical solution to counter the demanding climate, topography and additional challenges of the local operating environment,” Bravo’s Head of Special Projects, Jonathan Ziebart said earlier.

While KMB chose diesel buses, Alexander Dennis unveiled its new “zero emission” double deckers in June this year

KMB did not answer questions on why it chose Alexander Dennis’ diesel bus over the firm’s new “zero emission” three-axle electric Enviro500EV CHARGE.

A US executive for Alexander Dennis said in June there was “no better or more sustainable way to move large numbers of passengers” than that electric double-decker.