INDIANAPOLIS FD RESPONDED TO A TOWNHOUSE FIRE THIS MORNING. EG02 ARRIVED TO FIND HEAVY SMOKE SHOWING, LAYED A 5" LINE AND ESTABLISHED COMMAND. EG24 LAYED A 2ND 5" LINE. FIRE WAS ON THE 2ND FLOOR ON THE SOUTH END OF THE BLDG. AGGRESSIVE ATTACK WAS MADE. FIRE SOON SPREAD INTO THE ATTIC AND WAS TRAVELING NORTHWARD. AS LAD 34 WAS VENTING THE ROOF, EG24 CREW BECAME TRAPPED. THEY MADE THEIR WAY TO A BURNING BALCONY. IT IMMEDIATELY COLLAPSED INJURING 3 FIREFIGHTERS. THE FIRE SOON HAD POSSESSION OF THE ATTIC. A 2ND ALARM WAS SOUNDED. AN ATTEMPT TO HEAD OFF THE FIRE IN THE ATTIC WAS SUCCESSFUL. ONE THIRD OF THE BLDG WAS SAVED. WARREN TWP SENT 2 EG'S A LADDER TO ASSIST ON THE FAR EDGE OF THE CITY FIRE. 6 EG'S 3 LAD'S WERE USED.