notadriver
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- 1 Oct 2010
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- 3,735
If the transmission settings on the CAF units are the same as they are on buses, then ECO will use the gears to keep the engine RPM as low as possible, which means that each shift up may occur before the engine has reached the RPM at which it develops its peak torque (read: sacrifices acceleration to enhance fuel economy and engine longevity).
The other transmission mode, sometimes called Normal, Balanced, Automatic, or Power, changes the shift positions depending on the power demand the driver asks for. If the driver is only using low power then the gearbox will likely shift up at a similar RPM as it does in ECO mode because a high acceleration is not required. If the driver is using a lot or full power (i.e. asking for maximum acceleration) then the gearbox will attempt to keep the engine RPM within the engines' peak torque range, resulting in a higher overall RPM. On buses and coaches, the engine's peak torque range is shown by the green band on the tachometer
There is a performance requirement for trains to keep to time whereas buses are normally always set to max eco.