I think that this failure would not affect the calls on TRX2, unless they are not on timeslots 0 and 1, because the signalisation during dedicated mode is using SACCH which is on the same TS as the TCH.
After the fail of TRX1 the BCCH and SDCCH will be trasferred immediatly to TRX2.
I hope it is helpfull to you.