TJC used to be the top 5 until a few years back. So the general rankings were RI HCI VJ NJ TJ. TJ is one of the older JCs. It the oldest in the east at least. Celebrating its 40th year this year.
Anyways, so VJ came in and kick TJ in the nuts and so TJ was 5th. Not too shabby. But then in 2012 or 2011, ACJC beat TJC in terms of cutoff points to enter. Now in terms of cutoffs TJC was not even in the top 5. Next came NYJC which had been improving all this time and now NYJC has a stricter cutoff than TJ.
TJ is currently tied in with AJC which was never even close to matching up to TJ.
People have many theories for TJ's downfall. One of the most common one is the new principal who joined TJ, Susan Leong. She was the ex-principal of AJC and apparently they celebrated her leave if rumours are to be trusted. However before AJC, Susan Leong was the principal of Cedar and she was loved there and had worked a lot to bring up Cedar to where it is today. So now she came to TJC and started messing up the administration. Even teachers used to make fun of her sometimes. Well but imo I don't think one person is capable of bringing an entire school down although she might have played a part (Sorry Ms Leong).
Another reason is that the birth rate in the east is declining. So the number of applicants to JCs in the east is low. Everyone's first choice is always VJ so the demand for TJ has dropped tremendously recently. The cutoffs are based on demand and supply and not on results but the better students you get, the generally better the results are. So, TJ has been doing poorly for A Levels generally.
I don't think it's vastly different from NYJC's results but NYJC has seen a tremendous spike in L1R5 cutoffs. TJ has a new principal now, who is, if we believe the rumours, no better than Susan Leong.
So, TJ's future seems somewhat bleak right now. Yet TJ has a long history and although no recent achievements, the achievement boards in the school will tell you that TJ was an extremely well to do JC.