I actually meant that 340U (along with 341S & 286T), were
once 199 buses... Then they all got transfered to 179 when it was
introduced along with the super fast drivers. 
Anyway, when 340U accelerated out of BNL today, there something
like a bang sound! 
But talking about weird bus sounds.... go listen to 9162H of 179...
The engine goes tak tak tak tak tak and the ZF gearbox is very
distinctive compared to other LOs...