The System thinks it's busy. Have you tried to disconnect the line from the TLU? There could be a fault on the line causing the trunk to hang in this state.
A restart of TLP11 and/or DTR in LIM 2 should release it but this will affect other traffic.
Or you could try-
SGSAI:LIM=2,SIGAR=1,LEVEL=A,UNIT=TLP11,SIGNAM=CRADRRELEASE,STYPE=SWSW,BYTE=0-00&1-58&2-00;
SGSSI:SIGAR=1;