Neil Williams ) gurgled happily, sounding
much like they were saying :

A modern double decker is about 150% the weight of an RM.

It's also bigger, and has either a higher passenger capacity, a
wheelchair/buggy area or more legroom. These characteristics are
considered desirable. If a modern decker was the same size as a RM, I
very much doubt it'd be a lot heavier.

Is a modern double 50% larger, then?

A bloatibus is about 250% the weight.

And has a higher (admittedly standing) passenger capacity.

150% higher?