This was never taken away - this is a result of the newer versions of trainz not notifying when the horn key is pressed as it used to. for whatever reason this no longer registers so the auto bell never comes on. i don't have any further ideas on how to address it.
With JR slowly making their way through modern GEVO models, I reckon CP ones are in the pipeline at some point Soon(TM). CWMs would be cool though, now that CP, CSX, and UP all have them.