[Savage GT]

Does it still run for 30 seconds after you lift the trigger?

(I once spent a memorable evening in the signal box of a large marshaling yard directing engines like that to push lines of waggons over the hump when they then rolled down to whichever branch the points directed them.)

Trigger ?? 
no once its diallled to a stop it stops, how quickly depends on the deceleration setting.
As its digital, the chip remembers the last command or throttle position if no further command received, ie no power from the track.
On the blue tooth decoders (and one presumes with the forthcoming legacy dongle that will allow blue tooth on non BT decoders through the controller) you could lift it off the track and increase the speed if desired !
However, I am assuming the stay alive does negate the emergency stop button for averting imminent disasters when I forget to set the points correctly.
As this is a shunter, so will not be going fast and not often sharing the mainline with the faster locos, hopefully that won't be an issue 

@Anthony B, yes the best way TBH, but with British outline TT1:120 its all to new. There are odd bits becoming available, but not for much less than new atm, especially given the decent discounts and incentives us early adopters got from Hornby !