Doesn't mean bigger engine = more fuel consumed. A smaller
engine can consume a lot more fuel if its not suited for the type
of operation. There are articles online about car engine sizes and
whether smaller engines are more efificient and the general opinion
is that it is not really true, and I'm sure it is the case for
buses.
Also take note that besides SMRT not doing well on their bus
business, the bus business of SBS is also loss making for years,
the last annual report (for the FY2014), SBS incurred a $13.5m loss
on their bus business.
If youre running a transport business,road tax and insurance is
one of your concern,if a 1.5 turbo diesel can did the job well as a
2.5 twin turbo diesel which one do you choose?Im not saying A22 is
fuel guzzler but the maintenance price is higher than those normal
turbodiesel buses let alone the parts.