POSSIBLE CONFLICT.

Narrative

MY ACFT B-737-300 FLT ENRTE FROM BUR TO DEN ON MAR/XX/94. I WAS CLRED FOR THE PROFILE DSCNT INTO DEN WITH THE 250 KT AIRSPD CONSTRAINT AT BYSON INTXN REMOVED. I INFORMED ZDV THAT I INTENDED TO MAINTAIN 300 KTS IN MY DSCNT UNTIL REACHING BYSON AT 17000 FT. ATC CONCURRED. WHEN APCHING BYSON; ZDV INFORMED ME OF SLOW MOVING SWBOUND TFC AT 15200 FT N A CLB IN MY 11 O'CLOCK POS. SINCE I COULD NOT IMMEDIATELY SEE THE TARGET; I EXPANDED THE RANGE SCALE ON MY HSI TCASII PRESENTATION TO GIVE ME A BETTER PICTURE OF THE DEVELOPING SIT. I INDICATED TO ZDV THAT I HAD THE TARGET ON TCASII; IT WAS STILL CLBING SW TOWARD BYSON AS WE CONTINUED OUR AUTOFLT VNAV DSCNT; FINALLY THE TCASII TA WARNING ALERTED US JUST AS WE STARTED A TURN TO THE R TO AVOID A RAPIDLY DEVELOPING ALT CONFLICT. AS THE TA/RA ALERT WAS SOUNDED BY OUR EQUIP; AND WE IMMEDIATELY RESPONDED WITH THE NOSE UP CONFLICT RESOLUTION; THE ACFT WAS SPOTTED TO OUR L IN OUR 10:30 POS; AT OUR ALT; QUITE CLOSE TO US. TCASII MAY HAVE SAVED US FROM A MIDAIR. DURING THE FLASH MOMENT THAT I WAS ABLE TO OBSERVE THE ACFT; I SAW IT TO BE A HIGH WING; MULTI-ENG PROP. OUR TCASII DEV CAUSED US TO CLB 600-700 FT; THEREBY BREAKING THE ALT CONSTRAINT AT BYSON. TCASII DID WHAT IT WAS DESIGNED TO DO. THE REMAINDER OF THE FLT WAS UNEVENTFUL WITH A SAFE LNDG AT DEN. I PERCEIVED THE 'SLOW MOVING' ACFT TO ALSO BE SLOW CLBING. WRONG. THE FELLOW WAS OBVIOUSLY A TURBINE PWRED ACFT. BECAUSE HE WAS CLBING MUCH FASTER THAN I THOUGHT. THIS WHOLE SCENARIO TOOK PLACE IN ABOUT 1 MIN. I ALSO FORGOT TO FACTOR IN THE DELAY ON THE TCASII DISPLAY FOR POS AND ALT. TO ADD TO THE CONFUSION; I HAD EXPERIENCED A TCASII ARR INTO BUR THE PREVIOUS DAY (A SUNDAY) WITH NUMEROUS SMALL TCASII TARGETS WITH MINIMAL PERFORMANCE DEMONSTRATED. THE EXPERIENCE LULLED ME INTO THINKING 'SLOW MOVING' ALSO MEANT SLOW CLB PERFORMANCE.